diff --git a/atom/browser/api/atom_api_browser_window.cc b/atom/browser/api/atom_api_browser_window.cc
index def064086256..8c7aa222e2f4 100644
--- a/atom/browser/api/atom_api_browser_window.cc
+++ b/atom/browser/api/atom_api_browser_window.cc
@@ -13,6 +13,7 @@
 #include "atom/browser/web_contents_preferences.h"
 #include "atom/browser/window_list.h"
 #include "atom/common/api/api_messages.h"
+#include "atom/common/color_util.h"
 #include "atom/common/native_mate_converters/callback.h"
 #include "atom/common/native_mate_converters/file_path_converter.h"
 #include "atom/common/native_mate_converters/gfx_converter.h"
@@ -276,7 +277,6 @@ bool BrowserWindow::OnMessageReceived(const IPC::Message& message,
 void BrowserWindow::OnCloseContents() {
   if (!web_contents())
     return;
-  Observe(nullptr);
 
   // Close all child windows before closing current window.
   v8::Locker locker(isolate());
@@ -296,6 +296,9 @@ void BrowserWindow::OnCloseContents() {
 
   // Do not sent "unresponsive" event after window is closed.
   window_unresponsive_closure_.Cancel();
+
+  // Clear the web_contents() at last.
+  Observe(nullptr);
 }
 
 void BrowserWindow::OnRendererResponsive() {
@@ -307,6 +310,10 @@ void BrowserWindow::WillCloseWindow(bool* prevent_default) {
   *prevent_default = Emit("close");
 }
 
+void BrowserWindow::RequestPreferredWidth(int* width) {
+  *width = web_contents()->GetPreferredSize().width();
+}
+
 void BrowserWindow::OnCloseButtonClicked(bool* prevent_default) {
   // When user tries to close the window by clicking the close button, we do
   // not close the window immediately, instead we try to close the web page
@@ -356,10 +363,27 @@ void BrowserWindow::OnWindowEndSession() {
 }
 
 void BrowserWindow::OnWindowBlur() {
+  web_contents()->StoreFocus();
+#if defined(OS_MACOSX)
+  auto* rwhv = web_contents()->GetRenderWidgetHostView();
+  if (rwhv)
+    rwhv->SetActive(false);
+#endif
+
   Emit("blur");
 }
 
 void BrowserWindow::OnWindowFocus() {
+  web_contents()->RestoreFocus();
+#if defined(OS_MACOSX)
+  auto* rwhv = web_contents()->GetRenderWidgetHostView();
+  if (rwhv)
+    rwhv->SetActive(true);
+#else
+  if (!api_web_contents_->IsDevToolsOpened())
+    web_contents()->Focus();
+#endif
+
   Emit("focus");
 }
 
@@ -388,6 +412,10 @@ void BrowserWindow::OnWindowRestore() {
 }
 
 void BrowserWindow::OnWindowResize() {
+#if defined(OS_MACOSX)
+  if (!draggable_regions_.empty())
+    UpdateDraggableRegions(nullptr, draggable_regions_);
+#endif
   Emit("resize");
 }
 
@@ -754,7 +782,11 @@ bool BrowserWindow::IsKiosk() {
 }
 
 void BrowserWindow::SetBackgroundColor(const std::string& color_name) {
-  window_->SetBackgroundColor(color_name);
+  SkColor color = ParseHexColor(color_name);
+  window_->SetBackgroundColor(color);
+  auto* view = web_contents()->GetRenderWidgetHostView();
+  if (view)
+    view->SetBackgroundColor(color);
 }
 
 void BrowserWindow::SetHasShadow(bool has_shadow) {
@@ -774,15 +806,16 @@ double BrowserWindow::GetOpacity() {
 }
 
 void BrowserWindow::FocusOnWebView() {
-  window_->FocusOnWebView();
+  web_contents()->GetRenderViewHost()->GetWidget()->Focus();
 }
 
 void BrowserWindow::BlurWebView() {
-  window_->BlurWebView();
+  web_contents()->GetRenderViewHost()->GetWidget()->Blur();
 }
 
 bool BrowserWindow::IsWebViewFocused() {
-  return window_->IsWebViewFocused();
+  auto host_view = web_contents()->GetRenderViewHost()->GetWidget()->GetView();
+  return host_view && host_view->HasFocus();
 }
 
 void BrowserWindow::SetRepresentedFilename(const std::string& filename) {
@@ -1091,8 +1124,17 @@ void BrowserWindow::AddTabbedWindow(NativeWindow* window,
 
 void BrowserWindow::SetVibrancy(mate::Arguments* args) {
   std::string type;
-
   args->GetNext(&type);
+
+  auto* render_view_host = web_contents()->GetRenderViewHost();
+  if (render_view_host) {
+    auto* impl = content::RenderWidgetHostImpl::FromID(
+        render_view_host->GetProcess()->GetID(),
+        render_view_host->GetRoutingID());
+    if (impl)
+      impl->SetBackgroundOpaque(type.empty() ? !window_->transparent() : false);
+  }
+
   window_->SetVibrancy(type);
 }
 
@@ -1135,10 +1177,19 @@ void BrowserWindow::RemoveFromParentChildWindows() {
   parent->child_windows_.Remove(ID());
 }
 
-void BrowserWindow::UpdateDraggableRegions(
-    content::RenderFrameHost* rfh,
+// Convert draggable regions in raw format to SkRegion format.
+std::unique_ptr<SkRegion> BrowserWindow::DraggableRegionsToSkRegion(
     const std::vector<DraggableRegion>& regions) {
-  window_->UpdateDraggableRegions(regions);
+  std::unique_ptr<SkRegion> sk_region(new SkRegion);
+  for (const DraggableRegion& region : regions) {
+    sk_region->op(
+        region.bounds.x(),
+        region.bounds.y(),
+        region.bounds.right(),
+        region.bounds.bottom(),
+        region.draggable ? SkRegion::kUnion_Op : SkRegion::kDifference_Op);
+  }
+  return sk_region;
 }
 
 void BrowserWindow::ScheduleUnresponsiveEvent(int ms) {
diff --git a/atom/browser/api/atom_api_browser_window.h b/atom/browser/api/atom_api_browser_window.h
index 768d975e4647..82c2c017800f 100644
--- a/atom/browser/api/atom_api_browser_window.h
+++ b/atom/browser/api/atom_api_browser_window.h
@@ -81,6 +81,7 @@ class BrowserWindow : public mate::TrackableObject<BrowserWindow>,
 
   // NativeWindowObserver:
   void WillCloseWindow(bool* prevent_default) override;
+  void RequestPreferredWidth(int* width) override;
   void OnCloseButtonClicked(bool* prevent_default) override;
   void OnWindowClosed() override;
   void OnWindowEndSession() override;
@@ -260,6 +261,10 @@ class BrowserWindow : public mate::TrackableObject<BrowserWindow>,
       content::RenderFrameHost* rfh,
       const std::vector<DraggableRegion>& regions);
 
+  // Convert draggable regions in raw format to SkRegion format.
+  std::unique_ptr<SkRegion> DraggableRegionsToSkRegion(
+      const std::vector<DraggableRegion>& regions);
+
   // Schedule a notification unresponsive event.
   void ScheduleUnresponsiveEvent(int ms);
 
@@ -271,6 +276,10 @@ class BrowserWindow : public mate::TrackableObject<BrowserWindow>,
   MessageCallbackMap messages_callback_map_;
 #endif
 
+#if defined(OS_MACOSX)
+  std::vector<DraggableRegion> draggable_regions_;
+#endif
+
   // Closure that would be called when window is unresponsive when closing,
   // it should be cancelled when we can prove that the window is responsive.
   base::CancelableClosure window_unresponsive_closure_;
diff --git a/atom/browser/api/atom_api_browser_window_mac.mm b/atom/browser/api/atom_api_browser_window_mac.mm
new file mode 100644
index 000000000000..4e63e652b38d
--- /dev/null
+++ b/atom/browser/api/atom_api_browser_window_mac.mm
@@ -0,0 +1,120 @@
+// Copyright (c) 2018 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/api/atom_api_browser_window.h"
+
+#import <Cocoa/Cocoa.h>
+
+#include "atom/browser/native_browser_view.h"
+#include "atom/common/draggable_region.h"
+#include "base/mac/scoped_nsobject.h"
+
+@interface NSView (WebContentsView)
+- (void)setMouseDownCanMoveWindow:(BOOL)can_move;
+@end
+
+@interface ControlRegionView : NSView
+@end
+
+@implementation ControlRegionView
+
+- (BOOL)mouseDownCanMoveWindow {
+  return NO;
+}
+
+- (NSView*)hitTest:(NSPoint)aPoint {
+  return nil;
+}
+
+@end
+
+namespace atom {
+
+namespace api {
+
+namespace {
+
+// Return a vector of non-draggable regions that fill a window of size
+// |width| by |height|, but leave gaps where the window should be draggable.
+std::vector<gfx::Rect> CalculateNonDraggableRegions(
+    std::unique_ptr<SkRegion> draggable, int width, int height) {
+  std::vector<gfx::Rect> result;
+  std::unique_ptr<SkRegion> non_draggable(new SkRegion);
+  non_draggable->op(0, 0, width, height, SkRegion::kUnion_Op);
+  non_draggable->op(*draggable, SkRegion::kDifference_Op);
+  for (SkRegion::Iterator it(*non_draggable); !it.done(); it.next()) {
+    result.push_back(gfx::SkIRectToRect(it.rect()));
+  }
+  return result;
+}
+
+}  // namespace
+
+void BrowserWindow::UpdateDraggableRegions(
+    content::RenderFrameHost* rfh,
+    const std::vector<DraggableRegion>& regions) {
+  if (window_->has_frame())
+    return;
+
+  // All ControlRegionViews should be added as children of the WebContentsView,
+  // because WebContentsView will be removed and re-added when entering and
+  // leaving fullscreen mode.
+  NSView* webView = web_contents()->GetNativeView();
+  NSInteger webViewWidth = NSWidth([webView bounds]);
+  NSInteger webViewHeight = NSHeight([webView bounds]);
+
+  if ([webView respondsToSelector:@selector(setMouseDownCanMoveWindow:)]) {
+    [webView setMouseDownCanMoveWindow:YES];
+  }
+
+  // Remove all ControlRegionViews that are added last time.
+  // Note that [webView subviews] returns the view's mutable internal array and
+  // it should be copied to avoid mutating the original array while enumerating
+  // it.
+  base::scoped_nsobject<NSArray> subviews([[webView subviews] copy]);
+  for (NSView* subview in subviews.get())
+    if ([subview isKindOfClass:[ControlRegionView class]])
+      [subview removeFromSuperview];
+
+  // Draggable regions is implemented by having the whole web view draggable
+  // (mouseDownCanMoveWindow) and overlaying regions that are not draggable.
+  draggable_regions_ = regions;
+  std::vector<gfx::Rect> system_drag_exclude_areas;
+  if (regions.empty()) {
+    system_drag_exclude_areas.push_back(
+        gfx::Rect(0, 0, webViewWidth, webViewHeight));
+  } else {
+    CalculateNonDraggableRegions(
+        DraggableRegionsToSkRegion(regions), webViewWidth, webViewHeight);
+  }
+
+  if (window_->browser_view())
+    window_->browser_view()->UpdateDraggableRegions(system_drag_exclude_areas);
+
+  // Create and add a ControlRegionView for each region that needs to be
+  // excluded from the dragging.
+  for (std::vector<gfx::Rect>::const_iterator iter =
+           system_drag_exclude_areas.begin();
+       iter != system_drag_exclude_areas.end();
+       ++iter) {
+    base::scoped_nsobject<NSView> controlRegion(
+        [[ControlRegionView alloc] initWithFrame:NSZeroRect]);
+    [controlRegion setFrame:NSMakeRect(iter->x(),
+                                       webViewHeight - iter->bottom(),
+                                       iter->width(),
+                                       iter->height())];
+    [webView addSubview:controlRegion];
+  }
+
+  // AppKit will not update its cache of mouseDownCanMoveWindow unless something
+  // changes. Previously we tried adding an NSView and removing it, but for some
+  // reason it required reposting the mouse-down event, and didn't always work.
+  // Calling the below seems to be an effective solution.
+  [[webView window] setMovableByWindowBackground:NO];
+  [[webView window] setMovableByWindowBackground:YES];
+}
+
+}  // namespace api
+
+}  // namespace atom
diff --git a/atom/browser/api/atom_api_browser_window_views.cc b/atom/browser/api/atom_api_browser_window_views.cc
new file mode 100644
index 000000000000..75043a83e308
--- /dev/null
+++ b/atom/browser/api/atom_api_browser_window_views.cc
@@ -0,0 +1,24 @@
+// Copyright (c) 2018 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/api/atom_api_browser_window.h"
+
+#include "atom/browser/native_window_views.h"
+
+namespace atom {
+
+namespace api {
+
+void BrowserWindow::UpdateDraggableRegions(
+    content::RenderFrameHost* rfh,
+    const std::vector<DraggableRegion>& regions) {
+  if (window_->has_frame())
+    return;
+  static_cast<NativeWindowViews*>(window_.get())->UpdateDraggableRegions(
+      DraggableRegionsToSkRegion(regions));
+}
+
+}  // namespace api
+
+}  // namespace atom
diff --git a/atom/browser/api/atom_api_menu_mac.mm b/atom/browser/api/atom_api_menu_mac.mm
index 1a0aba3894b3..ed491730a114 100644
--- a/atom/browser/api/atom_api_menu_mac.mm
+++ b/atom/browser/api/atom_api_menu_mac.mm
@@ -48,10 +48,7 @@ void MenuMac::PopupOnUI(const base::WeakPtr<NativeWindow>& native_window,
                         base::Closure callback) {
   if (!native_window)
     return;
-  brightray::InspectableWebContents* web_contents =
-      native_window->inspectable_web_contents();
-  if (!web_contents)
-    return;
+  NSWindow* nswindow = native_window->GetNativeWindow();
 
   auto close_callback = base::Bind(
       &MenuMac::OnClosed, weak_factory_.GetWeakPtr(), window_id, callback);
@@ -59,7 +56,7 @@ void MenuMac::PopupOnUI(const base::WeakPtr<NativeWindow>& native_window,
       [[AtomMenuController alloc] initWithModel:model()
                           useDefaultAccelerator:NO]);
   NSMenu* menu = [popup_controllers_[window_id] menu];
-  NSView* view = web_contents->GetView()->GetNativeView();
+  NSView* view = [nswindow contentView];
 
   // Which menu item to show.
   NSMenuItem* item = nil;
@@ -69,7 +66,6 @@ void MenuMac::PopupOnUI(const base::WeakPtr<NativeWindow>& native_window,
   // (-1, -1) means showing on mouse location.
   NSPoint position;
   if (x == -1 || y == -1) {
-    NSWindow* nswindow = native_window->GetNativeWindow();
     position = [view convertPoint:[nswindow mouseLocationOutsideOfEventStream]
                          fromView:nil];
   } else {
diff --git a/atom/browser/api/atom_api_menu_views.cc b/atom/browser/api/atom_api_menu_views.cc
index 7fdfe0c134a6..6e710838ac0c 100644
--- a/atom/browser/api/atom_api_menu_views.cc
+++ b/atom/browser/api/atom_api_menu_views.cc
@@ -24,19 +24,16 @@ MenuViews::MenuViews(v8::Isolate* isolate, v8::Local<v8::Object> wrapper)
 void MenuViews::PopupAt(BrowserWindow* window,
                         int x, int y, int positioning_item,
                         const base::Closure& callback) {
-  NativeWindow* native_window = static_cast<NativeWindow*>(window->window());
+  auto* native_window = static_cast<NativeWindowViews*>(window->window());
   if (!native_window)
     return;
-  auto* web_contents = native_window->inspectable_web_contents();
-  if (!web_contents)
-    return;
 
   // (-1, -1) means showing on mouse location.
   gfx::Point location;
   if (x == -1 || y == -1) {
     location = display::Screen::GetScreen()->GetCursorScreenPoint();
   } else {
-    auto* view = web_contents->GetView()->GetWebView();
+    views::View* view = native_window;  // the instance is also its content view
     gfx::Point origin = view->bounds().origin();
     location = gfx::Point(origin.x() + x, origin.y() + y);
   }
@@ -53,7 +50,7 @@ void MenuViews::PopupAt(BrowserWindow* window,
   menu_runners_[window_id] = std::unique_ptr<MenuRunner>(new MenuRunner(
       model(), flags, close_callback));
   menu_runners_[window_id]->RunMenuAt(
-      static_cast<NativeWindowViews*>(window->window())->widget(),
+      native_window->widget(),
       NULL,
       gfx::Rect(location, gfx::Size()),
       views::MENU_ANCHOR_TOPLEFT,
diff --git a/atom/browser/atom_browser_client.cc b/atom/browser/atom_browser_client.cc
index c83a99c2b387..69fd274f6e80 100644
--- a/atom/browser/atom_browser_client.cc
+++ b/atom/browser/atom_browser_client.cc
@@ -33,6 +33,7 @@
 #include "chrome/browser/speech/tts_message_filter.h"
 #include "content/public/browser/browser_ppapi_host.h"
 #include "content/public/browser/client_certificate_delegate.h"
+#include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/resource_dispatcher_host.h"
diff --git a/atom/browser/atom_javascript_dialog_manager.cc b/atom/browser/atom_javascript_dialog_manager.cc
index 1f0536b4c292..4168be35361d 100644
--- a/atom/browser/atom_javascript_dialog_manager.cc
+++ b/atom/browser/atom_javascript_dialog_manager.cc
@@ -64,8 +64,10 @@ void AtomJavaScriptDialogManager::RunJavaScriptDialog(
       checkbox_string = "Prevent this app from creating additional dialogs";
     }
   }
+
+  auto* relay = NativeWindowRelay::FromWebContents(web_contents);
   atom::ShowMessageBox(
-      NativeWindow::FromWebContents(web_contents),
+      relay ? relay->window.get() : nullptr,
       atom::MessageBoxType::MESSAGE_BOX_TYPE_NONE, buttons, -1, 0,
       atom::MessageBoxOptions::MESSAGE_BOX_NONE, "",
       base::UTF16ToUTF8(message_text), "", checkbox_string,
diff --git a/atom/browser/browser_mac.mm b/atom/browser/browser_mac.mm
index 0faeee36f939..8f13626b9f4d 100644
--- a/atom/browser/browser_mac.mm
+++ b/atom/browser/browser_mac.mm
@@ -17,6 +17,7 @@
 #include "base/strings/sys_string_conversions.h"
 #include "brightray/common/application_info.h"
 #include "net/base/mac/url_conversions.h"
+#include "ui/gfx/image/image.h"
 #include "url/gurl.h"
 
 namespace atom {
diff --git a/atom/browser/native_window.cc b/atom/browser/native_window.cc
index 122215124839..ee8ba1dc87da 100644
--- a/atom/browser/native_window.cc
+++ b/atom/browser/native_window.cc
@@ -8,36 +8,12 @@
 #include <utility>
 #include <vector>
 
-#include "atom/browser/atom_browser_context.h"
-#include "atom/browser/atom_browser_main_parts.h"
 #include "atom/browser/browser.h"
 #include "atom/browser/window_list.h"
-#include "atom/common/draggable_region.h"
-#include "atom/common/native_mate_converters/file_path_converter.h"
+#include "atom/common/color_util.h"
 #include "atom/common/options_switches.h"
-#include "base/files/file_util.h"
-#include "base/json/json_writer.h"
-#include "base/message_loop/message_loop.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/threading/thread_task_runner_handle.h"
 #include "brightray/browser/inspectable_web_contents.h"
-#include "brightray/browser/inspectable_web_contents_view.h"
-#include "components/prefs/pref_service.h"
-#include "content/public/browser/navigation_entry.h"
-#include "content/public/browser/plugin_service.h"
-#include "content/public/browser/render_process_host.h"
-#include "content/public/browser/render_view_host.h"
-#include "content/public/browser/render_widget_host.h"
-#include "content/public/browser/render_widget_host_view.h"
-#include "content/public/common/content_switches.h"
-#include "ipc/ipc_message_macros.h"
 #include "native_mate/dictionary.h"
-#include "third_party/skia/include/core/SkRegion.h"
-#include "ui/gfx/codec/png_codec.h"
-#include "ui/gfx/geometry/point.h"
-#include "ui/gfx/geometry/rect.h"
-#include "ui/gfx/geometry/size.h"
-#include "ui/gfx/geometry/size_conversions.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(atom::NativeWindowRelay);
 
@@ -47,8 +23,7 @@ NativeWindow::NativeWindow(
     brightray::InspectableWebContents* inspectable_web_contents,
     const mate::Dictionary& options,
     NativeWindow* parent)
-    : content::WebContentsObserver(inspectable_web_contents->GetWebContents()),
-      has_frame_(true),
+    : has_frame_(true),
       transparent_(false),
       enable_larger_than_screen_(false),
       is_closed_(false),
@@ -58,7 +33,7 @@ NativeWindow::NativeWindow(
       parent_(parent),
       is_modal_(false),
       is_osr_dummy_(false),
-      inspectable_web_contents_(inspectable_web_contents),
+      browser_view_(nullptr),
       weak_factory_(this) {
   options.Get(options::kFrame, &has_frame_);
   options.Get(options::kTransparent, &transparent_);
@@ -76,16 +51,6 @@ NativeWindow::~NativeWindow() {
   NotifyWindowClosed();
 }
 
-// static
-NativeWindow* NativeWindow::FromWebContents(
-    content::WebContents* web_contents) {
-  for (const auto& window : WindowList::GetWindows()) {
-    if (window->web_contents() == web_contents)
-      return window;
-  }
-  return nullptr;
-}
-
 void NativeWindow::InitFromOptions(const mate::Dictionary& options) {
   // Setup window from options.
   int x = -1, y = -1;
@@ -172,10 +137,10 @@ void NativeWindow::InitFromOptions(const mate::Dictionary& options) {
   }
   std::string color;
   if (options.Get(options::kBackgroundColor, &color)) {
-    SetBackgroundColor(color);
+    SetBackgroundColor(ParseHexColor(color));
   } else if (!transparent()) {
     // For normal window, use white as default background.
-    SetBackgroundColor("#FFFF");
+    SetBackgroundColor(SK_ColorWHITE);
   }
   std::string title(Browser::Get()->GetName());
   options.Get(options::kTitle, &title);
@@ -354,19 +319,6 @@ void NativeWindow::SetEscapeTouchBarItem(
     const mate::PersistentDictionary& item) {
 }
 
-void NativeWindow::FocusOnWebView() {
-  web_contents()->GetRenderViewHost()->GetWidget()->Focus();
-}
-
-void NativeWindow::BlurWebView() {
-  web_contents()->GetRenderViewHost()->GetWidget()->Blur();
-}
-
-bool NativeWindow::IsWebViewFocused() {
-  auto host_view = web_contents()->GetRenderViewHost()->GetWidget()->GetView();
-  return host_view && host_view->HasFocus();
-}
-
 void NativeWindow::SetAutoHideMenuBar(bool auto_hide) {
 }
 
@@ -402,6 +354,11 @@ void NativeWindow::PreviewFile(const std::string& path,
 void NativeWindow::CloseFilePreview() {
 }
 
+void NativeWindow::NotifyWindowRequestPreferredWith(int* width) {
+  for (NativeWindowObserver& observer : observers_)
+    observer.RequestPreferredWidth(width);
+}
+
 void NativeWindow::NotifyWindowCloseButtonClicked() {
   // First ask the observers whether we want to close.
   bool prevent_default = false;
@@ -563,18 +520,4 @@ void NativeWindow::NotifyWindowMessage(
 }
 #endif
 
-std::unique_ptr<SkRegion> NativeWindow::DraggableRegionsToSkRegion(
-    const std::vector<DraggableRegion>& regions) {
-  std::unique_ptr<SkRegion> sk_region(new SkRegion);
-  for (const DraggableRegion& region : regions) {
-    sk_region->op(
-        region.bounds.x(),
-        region.bounds.y(),
-        region.bounds.right(),
-        region.bounds.bottom(),
-        region.draggable ? SkRegion::kUnion_Op : SkRegion::kDifference_Op);
-  }
-  return sk_region;
-}
-
 }  // namespace atom
diff --git a/atom/browser/native_window.h b/atom/browser/native_window.h
index 7f12f5a23b76..219463ac1568 100644
--- a/atom/browser/native_window.h
+++ b/atom/browser/native_window.h
@@ -11,20 +11,13 @@
 #include <vector>
 
 #include "atom/browser/native_window_observer.h"
-#include "atom/browser/ui/accelerator_util.h"
 #include "atom/browser/ui/atom_menu_model.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/supports_user_data.h"
-#include "content/public/browser/readback_types.h"
-#include "content/public/browser/render_frame_host.h"
-#include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 #include "extensions/browser/app_window/size_constraints.h"
 #include "native_mate/persistent_dictionary.h"
-#include "ui/gfx/geometry/rect_f.h"
-#include "ui/gfx/image/image.h"
-#include "ui/gfx/image/image_skia.h"
 
 class SkRegion;
 
@@ -37,8 +30,10 @@ struct NativeWebKeyboardEvent;
 }
 
 namespace gfx {
+class Image;
 class Point;
 class Rect;
+class RectF;
 class Size;
 }
 
@@ -52,8 +47,7 @@ class NativeBrowserView;
 
 struct DraggableRegion;
 
-class NativeWindow : public base::SupportsUserData,
-                     public content::WebContentsObserver {
+class NativeWindow : public base::SupportsUserData {
  public:
   ~NativeWindow() override;
 
@@ -64,9 +58,6 @@ class NativeWindow : public base::SupportsUserData,
       const mate::Dictionary& options,
       NativeWindow* parent = nullptr);
 
-  // Find a window from its WebContents
-  static NativeWindow* FromWebContents(content::WebContents* web_contents);
-
   void InitFromOptions(const mate::Dictionary& options);
 
   virtual void Close() = 0;
@@ -138,7 +129,7 @@ class NativeWindow : public base::SupportsUserData,
   virtual bool IsSimpleFullScreen() = 0;
   virtual void SetKiosk(bool kiosk) = 0;
   virtual bool IsKiosk() = 0;
-  virtual void SetBackgroundColor(const std::string& color_name) = 0;
+  virtual void SetBackgroundColor(SkColor color) = 0;
   virtual void SetHasShadow(bool has_shadow) = 0;
   virtual bool HasShadow() = 0;
   virtual void SetOpacity(const double opacity) = 0;
@@ -194,11 +185,6 @@ class NativeWindow : public base::SupportsUserData,
   virtual void ToggleTabBar();
   virtual bool AddTabbedWindow(NativeWindow* window);
 
-  // Webview APIs.
-  virtual void FocusOnWebView();
-  virtual void BlurWebView();
-  virtual bool IsWebViewFocused();
-
   // Toggle the menu bar.
   virtual void SetAutoHideMenuBar(bool auto_hide);
   virtual bool IsMenuBarAutoHide();
@@ -221,10 +207,6 @@ class NativeWindow : public base::SupportsUserData,
   virtual gfx::Rect WindowBoundsToContentBounds(
       const gfx::Rect& bounds) const = 0;
 
-  // Called when the window needs to update its draggable region.
-  virtual void UpdateDraggableRegions(
-      const std::vector<DraggableRegion>& regions) = 0;
-
   base::WeakPtr<NativeWindow> GetWeakPtr() {
     return weak_factory_.GetWeakPtr();
   }
@@ -243,6 +225,7 @@ class NativeWindow : public base::SupportsUserData,
 
   // Public API used by platform-dependent delegates and observers to send UI
   // related notifications.
+  void NotifyWindowRequestPreferredWith(int* width);
   void NotifyWindowCloseButtonClicked();
   void NotifyWindowClosed();
   void NotifyWindowEndSession();
@@ -282,10 +265,6 @@ class NativeWindow : public base::SupportsUserData,
     observers_.RemoveObserver(obs);
   }
 
-  brightray::InspectableWebContents* inspectable_web_contents() const {
-    return inspectable_web_contents_;
-  }
-
   bool has_frame() const { return has_frame_; }
   void set_has_frame(bool has_frame) { has_frame_ = has_frame; }
 
@@ -295,6 +274,7 @@ class NativeWindow : public base::SupportsUserData,
   void set_is_offscreen_dummy(bool is_dummy) { is_osr_dummy_ = is_dummy; }
   bool is_offscreen_dummy() const { return is_osr_dummy_; }
 
+  NativeBrowserView* browser_view() const { return browser_view_; }
   NativeWindow* parent() const { return parent_; }
   bool is_modal() const { return is_modal_; }
 
@@ -303,10 +283,9 @@ class NativeWindow : public base::SupportsUserData,
                const mate::Dictionary& options,
                NativeWindow* parent);
 
-  // Convert draggable regions in raw format to SkRegion format. Caller is
-  // responsible for deleting the returned SkRegion instance.
-  std::unique_ptr<SkRegion> DraggableRegionsToSkRegion(
-      const std::vector<DraggableRegion>& regions);
+  void set_browser_view(NativeBrowserView* browser_view) {
+    browser_view_ = browser_view;
+  }
 
  private:
   // Whether window has standard frame.
@@ -343,8 +322,8 @@ class NativeWindow : public base::SupportsUserData,
   // Is this a dummy window for an offscreen WebContents.
   bool is_osr_dummy_;
 
-  // The page this window is viewing.
-  brightray::InspectableWebContents* inspectable_web_contents_;
+  // The browser view layer.
+  NativeBrowserView* browser_view_;
 
   // Observers of this window.
   base::ObserverList<NativeWindowObserver> observers_;
diff --git a/atom/browser/native_window_mac.h b/atom/browser/native_window_mac.h
index 2d856aa9a9db..b91a2a36c4ba 100644
--- a/atom/browser/native_window_mac.h
+++ b/atom/browser/native_window_mac.h
@@ -79,7 +79,7 @@ class NativeWindowMac : public NativeWindow {
   bool IsSimpleFullScreen() override;
   void SetKiosk(bool kiosk) override;
   bool IsKiosk() override;
-  void SetBackgroundColor(const std::string& color_name) override;
+  void SetBackgroundColor(SkColor color) override;
   void SetHasShadow(bool has_shadow) override;
   bool HasShadow() override;
   void SetOpacity(const double opacity) override;
@@ -119,8 +119,6 @@ class NativeWindowMac : public NativeWindow {
 
   gfx::Rect ContentBoundsToWindowBounds(const gfx::Rect& bounds) const;
   gfx::Rect WindowBoundsToContentBounds(const gfx::Rect& bounds) const;
-  void UpdateDraggableRegions(
-      const std::vector<DraggableRegion>& regions) override;
 
   // Set the attribute of NSWindow while work around a bug of zoom button.
   void SetStyleMask(bool on, NSUInteger flag);
@@ -137,24 +135,12 @@ class NativeWindowMac : public NativeWindow {
   bool zoom_to_page_width() const { return zoom_to_page_width_; }
   bool fullscreen_window_title() const { return fullscreen_window_title_; }
   bool simple_fullscreen() const { return always_simple_fullscreen_; }
-  const std::vector<DraggableRegion>& draggable_regions() const {
-    return draggable_regions_;
-  }
-
- protected:
-  // Return a vector of non-draggable regions that fill a window of size
-  // |width| by |height|, but leave gaps where the window should be draggable.
-  std::vector<gfx::Rect> CalculateNonDraggableRegions(
-      const std::vector<DraggableRegion>& regions, int width, int height);
 
  private:
   void InternalSetParentWindow(NativeWindow* parent, bool attach);
   void ShowWindowButton(NSWindowButton button);
 
-  void InstallView();
-  void UninstallView();
-
-  void SetRenderWidgetHostOpaque(bool opaque);
+  void InstallView(NSView* view);
 
   base::scoped_nsobject<AtomNSWindow> window_;
   base::scoped_nsobject<AtomNSWindowDelegate> window_delegate_;
@@ -165,10 +151,6 @@ class NativeWindowMac : public NativeWindow {
   // The view that will fill the whole frameless window.
   base::scoped_nsobject<FullSizeContentView> content_view_;
 
-  NativeBrowserView* browser_view_;
-
-  std::vector<DraggableRegion> draggable_regions_;
-
   bool is_kiosk_;
 
   bool was_fullscreen_;
diff --git a/atom/browser/native_window_mac.mm b/atom/browser/native_window_mac.mm
index f4ceaafd122b..ba91651a029f 100644
--- a/atom/browser/native_window_mac.mm
+++ b/atom/browser/native_window_mac.mm
@@ -12,8 +12,6 @@
 #include "atom/browser/native_browser_view_mac.h"
 #include "atom/browser/ui/cocoa/atom_touch_bar.h"
 #include "atom/browser/window_list.h"
-#include "atom/common/color_util.h"
-#include "atom/common/draggable_region.h"
 #include "atom/common/options_switches.h"
 #include "base/mac/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
@@ -21,15 +19,9 @@
 #include "brightray/browser/inspectable_web_contents.h"
 #include "brightray/browser/inspectable_web_contents_view.h"
 #include "brightray/browser/mac/event_dispatching_window.h"
-#include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/public/browser/browser_accessibility_state.h"
-#include "content/public/browser/render_process_host.h"
-#include "content/public/browser/render_view_host.h"
-#include "content/public/browser/render_widget_host_view.h"
-#include "content/public/browser/web_contents.h"
 #include "native_mate/dictionary.h"
 #include "skia/ext/skia_utils_mac.h"
-#include "third_party/skia/include/core/SkRegion.h"
 #include "ui/gfx/skia_util.h"
 
 namespace {
@@ -218,16 +210,14 @@ bool ScopedDisableResize::disable_resize_ = false;
   if ([[NSApp currentEvent] modifierFlags] & NSShiftKeyMask)
     return frame;
 
-  content::WebContents* web_contents = shell_->web_contents();
-  if (!web_contents)
-    return frame;
-
-  CGFloat page_width = static_cast<CGFloat>(
-      web_contents->GetPreferredSize().width());
-  NSRect window_frame = [window frame];
+  // Get preferred width from observers. Usually the page width.
+  int preferred_width = 0;
+  shell_->NotifyWindowRequestPreferredWith(&preferred_width);
 
   // Never shrink from the current size on zoom.
-  CGFloat zoomed_width = std::max(page_width, NSWidth(window_frame));
+  NSRect window_frame = [window frame];
+  CGFloat zoomed_width = std::max(static_cast<CGFloat>(preferred_width),
+                                  NSWidth(window_frame));
 
   // |frame| determines our maximum extents. We need to set the origin of the
   // frame -- and only move it left if necessary.
@@ -243,30 +233,10 @@ bool ScopedDisableResize::disable_resize_ = false;
 }
 
 - (void)windowDidBecomeMain:(NSNotification*)notification {
-  content::WebContents* web_contents = shell_->web_contents();
-  if (!web_contents)
-    return;
-
-  web_contents->RestoreFocus();
-
-  content::RenderWidgetHostView* rwhv = web_contents->GetRenderWidgetHostView();
-  if (rwhv)
-    rwhv->SetActive(true);
-
   shell_->NotifyWindowFocus();
 }
 
 - (void)windowDidResignMain:(NSNotification*)notification {
-  content::WebContents* web_contents = shell_->web_contents();
-  if (!web_contents)
-    return;
-
-  web_contents->StoreFocus();
-
-  content::RenderWidgetHostView* rwhv = web_contents->GetRenderWidgetHostView();
-  if (rwhv)
-    rwhv->SetActive(false);
-
   shell_->NotifyWindowBlur();
 }
 
@@ -296,7 +266,6 @@ bool ScopedDisableResize::disable_resize_ = false;
 }
 
 - (void)windowDidResize:(NSNotification*)notification {
-  shell_->UpdateDraggableRegions(shell_->draggable_regions());
   shell_->NotifyWindowResize();
 }
 
@@ -747,25 +716,6 @@ enum {
 
 @end
 
-@interface ControlRegionView : NSView
-@end
-
-@implementation ControlRegionView
-
-- (BOOL)mouseDownCanMoveWindow {
-  return NO;
-}
-
-- (NSView*)hitTest:(NSPoint)aPoint {
-  return nil;
-}
-
-@end
-
-@interface NSView (WebContentsView)
-- (void)setMouseDownCanMoveWindow:(BOOL)can_move;
-@end
-
 @interface AtomProgressBar : NSProgressIndicator
 @end
 
@@ -830,7 +780,6 @@ NativeWindowMac::NativeWindowMac(
     const mate::Dictionary& options,
     NativeWindow* parent)
     : NativeWindow(web_contents, options, parent),
-      browser_view_(nullptr),
       is_kiosk_(false),
       was_fullscreen_(false),
       zoom_to_page_width_(false),
@@ -1002,7 +951,7 @@ NativeWindowMac::NativeWindowMac(
   options.Get(options::kDisableAutoHideCursor, &disableAutoHideCursor);
   [window_ setDisableAutoHideCursor:disableAutoHideCursor];
 
-  NSView* view = inspectable_web_contents()->GetView()->GetNativeView();
+  NSView* view = web_contents->GetView()->GetNativeView();
   [view setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
 
   // Use an NSEvent monitor to listen for the wheel event.
@@ -1013,9 +962,6 @@ NativeWindowMac::NativeWindowMac(
       if ([[event window] windowNumber] != [window_ windowNumber])
         return event;
 
-      if (!web_contents)
-        return event;
-
       if (!began && (([event phase] == NSEventPhaseMayBegin) ||
                                  ([event phase] == NSEventPhaseBegan))) {
         this->NotifyWindowScrollTouchBegin();
@@ -1028,7 +974,7 @@ NativeWindowMac::NativeWindowMac(
       return event;
   }];
 
-  InstallView();
+  InstallView(web_contents->GetView()->GetNativeView());
 
   std::string type;
   if (options.Get(options::kVibrancyType, &type)) {
@@ -1042,7 +988,6 @@ NativeWindowMac::NativeWindowMac(
 
 NativeWindowMac::~NativeWindowMac() {
   [NSEvent removeMonitor:wheel_event_monitor_];
-  Observe(nullptr);
 }
 
 void NativeWindowMac::Close() {
@@ -1498,15 +1443,10 @@ bool NativeWindowMac::IsKiosk() {
   return is_kiosk_;
 }
 
-void NativeWindowMac::SetBackgroundColor(const std::string& color_name) {
-  SkColor color = ParseHexColor(color_name);
+void NativeWindowMac::SetBackgroundColor(SkColor color) {
   base::ScopedCFTypeRef<CGColorRef> cgcolor(
       skia::CGColorCreateFromSkColor(color));
   [[[window_ contentView] layer] setBackgroundColor:cgcolor];
-
-  const auto view = web_contents()->GetRenderWidgetHostView();
-  if (view)
-    view->SetBackgroundColor(color);
 }
 
 void NativeWindowMac::SetHasShadow(bool has_shadow) {
@@ -1550,20 +1490,19 @@ void NativeWindowMac::SetContentProtection(bool enable) {
                                  : NSWindowSharingReadOnly];
 }
 
-void NativeWindowMac::SetBrowserView(NativeBrowserView* browser_view) {
-  if (browser_view_) {
-    [browser_view_->GetInspectableWebContentsView()->GetNativeView()
+void NativeWindowMac::SetBrowserView(NativeBrowserView* view) {
+  if (browser_view()) {
+    [browser_view()->GetInspectableWebContentsView()->GetNativeView()
             removeFromSuperview];
-    browser_view_ = nullptr;
+    set_browser_view(nullptr);
   }
 
-  if (!browser_view) {
+  if (!view) {
     return;
   }
 
-  browser_view_ = browser_view;
-  auto* native_view =
-      browser_view->GetInspectableWebContentsView()->GetNativeView();
+  set_browser_view(view);
+  auto* native_view = view->GetInspectableWebContentsView()->GetNativeView();
   [[window_ contentView] addSubview:native_view
                          positioned:NSWindowAbove
                          relativeTo:nil];
@@ -1575,7 +1514,7 @@ void NativeWindowMac::SetParentWindow(NativeWindow* parent) {
 }
 
 gfx::NativeView NativeWindowMac::GetNativeView() const {
-  return inspectable_web_contents()->GetView()->GetNativeView();
+  return [window_ contentView];
 }
 
 gfx::NativeWindow NativeWindowMac::GetNativeWindow() const {
@@ -1583,7 +1522,7 @@ gfx::NativeWindow NativeWindowMac::GetNativeWindow() const {
 }
 
 gfx::AcceleratedWidget NativeWindowMac::GetAcceleratedWidget() const {
-  return inspectable_web_contents()->GetView()->GetNativeView();
+  return [window_ contentView];
 }
 
 void NativeWindowMac::SetProgressBar(double progress, const NativeWindow::ProgressState state) {
@@ -1681,20 +1620,6 @@ bool NativeWindowMac::AddTabbedWindow(NativeWindow* window) {
   return true;
 }
 
-void NativeWindowMac::SetRenderWidgetHostOpaque(bool opaque) {
-  if (!web_contents()) return;
-
-  auto render_view_host = web_contents()->GetRenderViewHost();
-  if (!render_view_host) return;
-
-  content::RenderWidgetHostImpl* impl = content::RenderWidgetHostImpl::FromID(
-      render_view_host->GetProcess()->GetID(),
-      render_view_host->GetRoutingID());
-  if (!impl) return;
-
-  impl->SetBackgroundOpaque(opaque);
-}
-
 void NativeWindowMac::SetVibrancy(const std::string& type) {
   if (!base::mac::IsAtLeastOS10_10()) return;
 
@@ -1705,7 +1630,6 @@ void NativeWindowMac::SetVibrancy(const std::string& type) {
       [window_ setBackgroundColor:background_color_before_vibrancy_];
       [window_ setTitlebarAppearsTransparent:transparency_before_vibrancy_];
     }
-    SetRenderWidgetHostOpaque(!transparent());
     if (vibrant_view == nil) return;
 
     [vibrant_view removeFromSuperview];
@@ -1714,7 +1638,6 @@ void NativeWindowMac::SetVibrancy(const std::string& type) {
     return;
   }
 
-  SetRenderWidgetHostOpaque(false);
   background_color_before_vibrancy_.reset([window_ backgroundColor]);
   transparency_before_vibrancy_ = [window_ titlebarAppearsTransparent];
 
@@ -1813,80 +1736,6 @@ gfx::Rect NativeWindowMac::WindowBoundsToContentBounds(
   }
 }
 
-void NativeWindowMac::UpdateDraggableRegions(
-    const std::vector<DraggableRegion>& regions) {
-  if (has_frame())
-    return;
-
-  // All ControlRegionViews should be added as children of the WebContentsView,
-  // because WebContentsView will be removed and re-added when entering and
-  // leaving fullscreen mode.
-  NSView* webView = web_contents()->GetNativeView();
-  NSInteger webViewWidth = NSWidth([webView bounds]);
-  NSInteger webViewHeight = NSHeight([webView bounds]);
-
-  if ([webView respondsToSelector:@selector(setMouseDownCanMoveWindow:)]) {
-    [webView setMouseDownCanMoveWindow:YES];
-  }
-
-  // Remove all ControlRegionViews that are added last time.
-  // Note that [webView subviews] returns the view's mutable internal array and
-  // it should be copied to avoid mutating the original array while enumerating
-  // it.
-  base::scoped_nsobject<NSArray> subviews([[webView subviews] copy]);
-  for (NSView* subview in subviews.get())
-    if ([subview isKindOfClass:[ControlRegionView class]])
-      [subview removeFromSuperview];
-
-  // Draggable regions is implemented by having the whole web view draggable
-  // (mouseDownCanMoveWindow) and overlaying regions that are not draggable.
-  draggable_regions_ = regions;
-  std::vector<gfx::Rect> system_drag_exclude_areas =
-      CalculateNonDraggableRegions(regions, webViewWidth, webViewHeight);
-
-  if (browser_view_)
-    browser_view_->UpdateDraggableRegions(system_drag_exclude_areas);
-
-  // Create and add a ControlRegionView for each region that needs to be
-  // excluded from the dragging.
-  for (std::vector<gfx::Rect>::const_iterator iter =
-           system_drag_exclude_areas.begin();
-       iter != system_drag_exclude_areas.end();
-       ++iter) {
-    base::scoped_nsobject<NSView> controlRegion(
-        [[ControlRegionView alloc] initWithFrame:NSZeroRect]);
-    [controlRegion setFrame:NSMakeRect(iter->x(),
-                                       webViewHeight - iter->bottom(),
-                                       iter->width(),
-                                       iter->height())];
-    [webView addSubview:controlRegion];
-  }
-
-  // AppKit will not update its cache of mouseDownCanMoveWindow unless something
-  // changes. Previously we tried adding an NSView and removing it, but for some
-  // reason it required reposting the mouse-down event, and didn't always work.
-  // Calling the below seems to be an effective solution.
-  [window_ setMovableByWindowBackground:NO];
-  [window_ setMovableByWindowBackground:YES];
-}
-
-std::vector<gfx::Rect> NativeWindowMac::CalculateNonDraggableRegions(
-    const std::vector<DraggableRegion>& regions, int width, int height) {
-  std::vector<gfx::Rect> result;
-  if (regions.empty()) {
-    result.push_back(gfx::Rect(0, 0, width, height));
-  } else {
-    std::unique_ptr<SkRegion> draggable(DraggableRegionsToSkRegion(regions));
-    std::unique_ptr<SkRegion> non_draggable(new SkRegion);
-    non_draggable->op(0, 0, width, height, SkRegion::kUnion_Op);
-    non_draggable->op(*draggable, SkRegion::kDifference_Op);
-    for (SkRegion::Iterator it(*non_draggable); !it.done(); it.next()) {
-      result.push_back(gfx::SkIRectToRect(it.rect()));
-    }
-  }
-  return result;
-}
-
 void NativeWindowMac::InternalSetParentWindow(NativeWindow* parent, bool attach) {
   if (is_modal())
     return;
@@ -1912,14 +1761,13 @@ void NativeWindowMac::ShowWindowButton(NSWindowButton button) {
   [view.superview addSubview:view positioned:NSWindowAbove relativeTo:nil];
 }
 
-void NativeWindowMac::InstallView() {
+void NativeWindowMac::InstallView(NSView* view) {
   // Make sure the bottom corner is rounded for non-modal windows: http://crbug.com/396264.
   // But do not enable it on OS X 10.9 for transparent window, otherwise a
   // semi-transparent frame would show.
   if (!(transparent() && base::mac::IsOS10_9()) && !is_modal())
     [[window_ contentView] setWantsLayer:YES];
 
-  NSView* view = inspectable_web_contents()->GetView()->GetNativeView();
   if (has_frame()) {
     [view setFrame:[[window_ contentView] bounds]];
     [[window_ contentView] addSubview:view];
@@ -1967,11 +1815,6 @@ void NativeWindowMac::InstallView() {
   }
 }
 
-void NativeWindowMac::UninstallView() {
-  NSView* view = inspectable_web_contents()->GetView()->GetNativeView();
-  [view removeFromSuperview];
-}
-
 void NativeWindowMac::SetStyleMask(bool on, NSUInteger flag) {
   // Changing the styleMask of a frameless windows causes it to change size so
   // we explicitly disable resizing while setting it.
diff --git a/atom/browser/native_window_observer.h b/atom/browser/native_window_observer.h
index 27f5cb92f8a3..4dfd3521091a 100644
--- a/atom/browser/native_window_observer.h
+++ b/atom/browser/native_window_observer.h
@@ -34,6 +34,9 @@ class NativeWindowObserver {
   // Called when the window is gonna closed.
   virtual void WillCloseWindow(bool* prevent_default) {}
 
+  // Called when the window wants to know the preferred width.
+  virtual void RequestPreferredWidth(int* width) {}
+
   // Called when closed button is clicked.
   virtual void OnCloseButtonClicked(bool* prevent_default) {}
 
diff --git a/atom/browser/native_window_views.cc b/atom/browser/native_window_views.cc
index 895f1b07f79a..46f4a5c1b746 100644
--- a/atom/browser/native_window_views.cc
+++ b/atom/browser/native_window_views.cc
@@ -16,7 +16,6 @@
 #include "atom/browser/web_contents_preferences.h"
 #include "atom/browser/web_view_manager.h"
 #include "atom/browser/window_list.h"
-#include "atom/common/color_util.h"
 #include "atom/common/draggable_region.h"
 #include "atom/common/native_mate_converters/image_converter.h"
 #include "atom/common/options_switches.h"
@@ -141,8 +140,8 @@ NativeWindowViews::NativeWindowViews(
     NativeWindow* parent)
     : NativeWindow(web_contents, options, parent),
       window_(new views::Widget),
-      web_view_(inspectable_web_contents()->GetView()->GetView()),
-      browser_view_(nullptr),
+      web_view_(web_contents->GetView()->GetView()),
+      focused_view_(web_contents->GetView()->GetWebView()),
       menu_bar_autohide_(false),
       menu_bar_visible_(false),
       menu_bar_alt_pressed_(false),
@@ -792,9 +791,8 @@ bool NativeWindowViews::IsKiosk() {
   return IsFullscreen();
 }
 
-void NativeWindowViews::SetBackgroundColor(const std::string& color_name) {
+void NativeWindowViews::SetBackgroundColor(SkColor background_color) {
   // web views' background color.
-  SkColor background_color = ParseHexColor(color_name);
   SetBackground(views::CreateSolidBackground(background_color));
 
 #if defined(OS_WIN)
@@ -950,22 +948,21 @@ void NativeWindowViews::SetMenu(AtomMenuModel* menu_model) {
   Layout();
 }
 
-void NativeWindowViews::SetBrowserView(NativeBrowserView* browser_view) {
-  if (browser_view_) {
+void NativeWindowViews::SetBrowserView(NativeBrowserView* view) {
+  if (browser_view()) {
     web_view_->RemoveChildView(
-        browser_view_->GetInspectableWebContentsView()->GetView());
-    browser_view_ = nullptr;
+        browser_view()->GetInspectableWebContentsView()->GetView());
+    set_browser_view(nullptr);
   }
 
-  if (!browser_view) {
+  if (!view) {
     return;
   }
 
   // Add as child of the main web view to avoid (0, 0) origin from overlapping
   // with menu bar.
-  browser_view_ = browser_view;
-  web_view_->AddChildView(
-      browser_view->GetInspectableWebContentsView()->GetView());
+  set_browser_view(view);
+  web_view_->AddChildView(view->GetInspectableWebContentsView()->GetView());
 }
 
 void NativeWindowViews::SetParentWindow(NativeWindow* parent) {
@@ -1123,11 +1120,8 @@ gfx::Rect NativeWindowViews::WindowBoundsToContentBounds(
 }
 
 void NativeWindowViews::UpdateDraggableRegions(
-    const std::vector<DraggableRegion>& regions) {
-  // Draggable region is not supported for non-frameless window.
-  if (has_frame())
-    return;
-  draggable_region_ = DraggableRegionsToSkRegion(regions);
+    std::unique_ptr<SkRegion> region) {
+  draggable_region_ = std::move(region);
 }
 
 #if defined(OS_WIN)
@@ -1190,10 +1184,6 @@ void NativeWindowViews::OnWidgetActivationChanged(
                           &NativeWindow::NotifyWindowBlur,
                  GetWeakPtr()));
 
-  if (active && inspectable_web_contents() &&
-      !inspectable_web_contents()->IsDevToolsViewShowing())
-    web_contents()->Focus();
-
   // Hide menu bar when window is blured.
   if (!active && menu_bar_autohide_ && menu_bar_visible_)
     SetMenuBarVisibility(false);
@@ -1208,9 +1198,9 @@ void NativeWindowViews::OnWidgetBoundsChanged(
   // handle minimized windows on Windows.
   const auto new_bounds = GetBounds();
   if (widget_size_ != new_bounds.size()) {
-    if (browser_view_) {
-      const auto flags = static_cast<NativeBrowserViewViews*>(browser_view_)
-                             ->GetAutoResizeFlags();
+    if (browser_view()) {
+      const auto flags = static_cast<NativeBrowserViewViews*>(browser_view())->
+          GetAutoResizeFlags();
       int width_delta = 0;
       int height_delta = 0;
       if (flags & kAutoResizeWidth) {
@@ -1220,7 +1210,7 @@ void NativeWindowViews::OnWidgetBoundsChanged(
         height_delta = new_bounds.height() - widget_size_.height();
       }
 
-      auto* view = browser_view_->GetInspectableWebContentsView()->GetView();
+      auto* view = browser_view()->GetInspectableWebContentsView()->GetView();
       auto new_view_size = view->size();
       new_view_size.set_width(new_view_size.width() + width_delta);
       new_view_size.set_height(new_view_size.height() + height_delta);
@@ -1246,7 +1236,7 @@ void NativeWindowViews::DeleteDelegate() {
 }
 
 views::View* NativeWindowViews::GetInitiallyFocusedView() {
-  return inspectable_web_contents()->GetView()->GetWebView();
+  return focused_view_;
 }
 
 bool NativeWindowViews::CanResize() const {
diff --git a/atom/browser/native_window_views.h b/atom/browser/native_window_views.h
index 73e91a92277a..da2a712d420e 100644
--- a/atom/browser/native_window_views.h
+++ b/atom/browser/native_window_views.h
@@ -101,7 +101,7 @@ class NativeWindowViews : public NativeWindow,
   bool IsSimpleFullScreen() override;
   void SetKiosk(bool kiosk) override;
   bool IsKiosk() override;
-  void SetBackgroundColor(const std::string& color_name) override;
+  void SetBackgroundColor(SkColor color) override;
   void SetHasShadow(bool has_shadow) override;
   bool HasShadow() override;
   void SetOpacity(const double opacity) override;
@@ -128,8 +128,8 @@ class NativeWindowViews : public NativeWindow,
 
   gfx::Rect ContentBoundsToWindowBounds(const gfx::Rect& bounds) const override;
   gfx::Rect WindowBoundsToContentBounds(const gfx::Rect& bounds) const override;
-  void UpdateDraggableRegions(
-      const std::vector<DraggableRegion>& regions) override;
+
+  void UpdateDraggableRegions(std::unique_ptr<SkRegion> region);
 
 #if defined(OS_WIN)
   void SetIcon(HICON small_icon, HICON app_icon);
@@ -214,8 +214,7 @@ class NativeWindowViews : public NativeWindow,
 
   std::unique_ptr<views::Widget> window_;
   views::View* web_view_;  // Managed by inspectable_web_contents_.
-
-  NativeBrowserView* browser_view_;
+  views::View* focused_view_;  // The view should be focused by default.
 
   std::unique_ptr<AutofillPopup> autofill_popup_;
 
diff --git a/atom/browser/web_contents_preferences.cc b/atom/browser/web_contents_preferences.cc
index 7951c36b4538..416508742198 100644
--- a/atom/browser/web_contents_preferences.cc
+++ b/atom/browser/web_contents_preferences.cc
@@ -209,11 +209,14 @@ void WebContentsPreferences::AppendExtraCommandLineSwitches(
     if (manager) {
       auto embedder = manager->GetEmbedder(guest_instance_id);
       if (embedder) {
-        auto window = NativeWindow::FromWebContents(embedder);
-        if (window) {
-          const bool visible = window->IsVisible() && !window->IsMinimized();
-          if (!visible) {
-            command_line->AppendSwitch(switches::kHiddenPage);
+        auto* relay = NativeWindowRelay::FromWebContents(web_contents);
+        if (relay) {
+          auto* window = relay->window.get();
+          if (window) {
+            const bool visible = window->IsVisible() && !window->IsMinimized();
+            if (!visible) {
+              command_line->AppendSwitch(switches::kHiddenPage);
+            }
           }
         }
       }
diff --git a/atom/browser/web_dialog_helper.cc b/atom/browser/web_dialog_helper.cc
index 1dd479883d87..878b4176a9d0 100644
--- a/atom/browser/web_dialog_helper.cc
+++ b/atom/browser/web_dialog_helper.cc
@@ -235,12 +235,8 @@ void WebDialogHelper::RunFileChooser(
         NOTREACHED();
     }
 
-    AtomBrowserContext* browser_context = static_cast<AtomBrowserContext*>(
-        window_->web_contents()->GetBrowserContext());
-    if (!browser_context) {
-      browser_context = static_cast<atom::AtomBrowserContext*>(
-          render_frame_host->GetProcess()->GetBrowserContext());
-    }
+    auto* browser_context = static_cast<atom::AtomBrowserContext*>(
+        render_frame_host->GetProcess()->GetBrowserContext());
     settings.default_path = browser_context->prefs()->GetFilePath(
         prefs::kSelectFileLastDirectory).Append(params.default_file_name);
     settings.properties = flags;
diff --git a/filenames.gypi b/filenames.gypi
index 38ba7b226e27..e051b4707e5c 100644
--- a/filenames.gypi
+++ b/filenames.gypi
@@ -163,6 +163,8 @@
       'atom/browser/api/atom_api_web_view_manager.cc',
       'atom/browser/api/atom_api_browser_window.cc',
       'atom/browser/api/atom_api_browser_window.h',
+      'atom/browser/api/atom_api_browser_window_mac.mm',
+      'atom/browser/api/atom_api_browser_window_views.cc',
       'atom/browser/api/event.cc',
       'atom/browser/api/event.h',
       'atom/browser/api/event_emitter.cc',