Show dummy view under offscreen mode

atom/browser/osr/osr_web_contents_view.cc

@@ -11,9 +11,15 @@ OffScreenWebContentsView::OffScreenWebContentsView(
     : transparent_(transparent),
       callback_(callback),
       web_contents_(nullptr) {
+#if defined(OS_MACOSX)
+  PlatformCreate();
+#endif
 }
 
 OffScreenWebContentsView::~OffScreenWebContentsView() {
+#if defined(OS_MACOSX)
+  PlatformDestroy();
+#endif
 }
 
 void OffScreenWebContentsView::SetWebContents(
@@ -21,6 +27,7 @@ void OffScreenWebContentsView::SetWebContents(
   web_contents_ = web_contents;
 }
 
+#if !defined(OS_MACOSX)
 gfx::NativeView OffScreenWebContentsView::GetNativeView() const {
   return gfx::NativeView();
 }
@@ -32,6 +39,7 @@ gfx::NativeView OffScreenWebContentsView::GetContentNativeView() const {
 gfx::NativeWindow OffScreenWebContentsView::GetTopLevelNativeWindow() const {
   return gfx::NativeWindow();
 }
+#endif
 
 void OffScreenWebContentsView::GetContainerBounds(gfx::Rect* out) const {
   *out = GetViewBounds();

atom/browser/osr/osr_web_contents_view.h

@@ -10,6 +10,14 @@
 #include "content/browser/web_contents/web_contents_view.h"
 #include "content/public/browser/web_contents.h"
 
+#if defined(OS_MACOSX)
+#ifdef __OBJC__
+@class OffScreenView;
+#else
+class OffScreenView;
+#endif
+#endif
+
 namespace atom {
 
 class OffScreenWebContentsView : public content::WebContentsView,
@@ -61,12 +69,21 @@ class OffScreenWebContentsView : public content::WebContentsView,
   void UpdateDragCursor(blink::WebDragOperation operation) override;
 
  private:
+#if defined(OS_MACOSX)
+  void PlatformCreate();
+  void PlatformDestroy();
+#endif
+
   const bool transparent_;
   OnPaintCallback callback_;
 
   // Weak refs.
   OffScreenRenderWidgetHostView* view_;
   content::WebContents* web_contents_;
+
+#if defined(OS_MACOSX)
+  OffScreenView* offScreenView_;
+#endif
 };
 
 }  // namespace atom

atom/browser/osr/osr_web_contents_view_mac.mm

@@ -0,0 +1,52 @@
+// Copyright (c) 2016 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/osr/osr_web_contents_view.h"
+
+@interface OffScreenView : NSView
+@end
+
+@implementation OffScreenView
+
+- (void)drawRect:(NSRect)dirtyRect {
+  NSString* str = @"No content under offscreen mode";
+  NSMutableParagraphStyle* paragraphStyle =
+      [[[NSParagraphStyle defaultParagraphStyle] mutableCopy] autorelease];
+  [paragraphStyle setAlignment:NSCenterTextAlignment];
+  NSDictionary* attributes = [NSDictionary
+      dictionaryWithObject:paragraphStyle
+                    forKey:NSParagraphStyleAttributeName];
+  NSAttributedString* text =
+      [[[NSAttributedString alloc] initWithString:str
+                                       attributes:attributes] autorelease];
+  NSRect frame = NSMakeRect(0, (self.frame.size.height - text.size.height) / 2,
+                            self.frame.size.width, text.size.height);
+  [str drawInRect:frame withAttributes:attributes];
+}
+
+@end
+
+namespace atom {
+
+gfx::NativeView OffScreenWebContentsView::GetNativeView() const {
+  return offScreenView_;
+}
+
+gfx::NativeView OffScreenWebContentsView::GetContentNativeView() const {
+  return offScreenView_;
+}
+
+gfx::NativeWindow OffScreenWebContentsView::GetTopLevelNativeWindow() const {
+  return [offScreenView_ window];
+}
+
+void OffScreenWebContentsView::PlatformCreate() {
+  offScreenView_ = [[OffScreenView alloc] init];
+}
+
+void OffScreenWebContentsView::PlatformDestroy() {
+  [offScreenView_ release];
+}
+
+}  // namespace atom

filenames.gypi

@@ -206,6 +206,7 @@
       'atom/browser/native_window_mac.h',
       'atom/browser/native_window_mac.mm',
       'atom/browser/native_window_observer.h',
+      'atom/browser/osr/osr_web_contents_view_mac.mm',
       'atom/browser/osr/osr_web_contents_view.cc',
       'atom/browser/osr/osr_web_contents_view.h',
       'atom/browser/osr/osr_output_device.cc',