use zoom factor webpreference option when required.

* When setzoomlevel is not called for the host.
* When there is no zoom preference for the host.

atom/browser/api/atom_api_web_contents.cc

@@ -68,6 +68,7 @@
 #include "content/public/common/context_menu_params.h"
 #include "native_mate/dictionary.h"
 #include "native_mate/object_template_builder.h"
+#include "net/base/url_util.h"
 #include "net/url_request/url_request_context.h"
 #include "third_party/WebKit/public/platform/WebInputEvent.h"
 #include "third_party/WebKit/public/web/WebFindOptions.h"
@@ -252,7 +253,8 @@ WebContents::WebContents(v8::Isolate* isolate,
       type_(type),
       request_id_(0),
       background_throttling_(true),
-      enable_devtools_(true) {
+      enable_devtools_(true),
+      zoom_factor_(content::kMinimumZoomFactor) {
 
   if (type == REMOTE) {
     web_contents->SetUserAgentOverride(GetBrowserContext()->GetUserAgent());
@@ -272,9 +274,11 @@ WebContents::WebContents(v8::Isolate* isolate,
       type_(BROWSER_WINDOW),
       request_id_(0),
       background_throttling_(true),
-      enable_devtools_(true) {
+      enable_devtools_(true),
+      zoom_factor_(content::kMinimumZoomFactor) {
   // Read options.
   options.Get("backgroundThrottling", &background_throttling_);
+  options.Get("zoomFactor", &zoom_factor_);
 
   // FIXME(zcbenz): We should read "type" parameter for better design, but
   // on Windows we have encountered a compiler bug that if we read "type"
@@ -734,6 +738,8 @@ void WebContents::DidFinishNavigation(
     auto url = navigation_handle->GetURL();
     bool is_in_page = navigation_handle->IsSamePage();
     if (is_main_frame && !is_in_page) {
+      // Set initial zoom factor if needed.
+      SetZoomFactorIfNeeded(url);
       Emit("did-navigate", url);
     } else if (is_in_page) {
       Emit("did-navigate-in-page", url, is_main_frame);
@@ -1500,6 +1506,15 @@ void WebContents::Invalidate() {
 }
 
 void WebContents::SetZoomLevel(double level) {
+  auto factor = content::ZoomLevelToZoomFactor(level);
+  if (!content::ZoomValuesEqual(zoom_factor_, factor)) {
+    content::NavigationEntry* entry =
+        web_contents()->GetController().GetLastCommittedEntry();
+    if (entry) {
+      std::string host = net::GetHostOrSpecFromURL(entry->GetURL());
+      host_zoom_factor_[host] = factor;
+    }
+  }
   content::HostZoomMap::SetZoomLevel(web_contents(), level);
 }
 
@@ -1517,6 +1532,22 @@ double WebContents::GetZoomFactor() {
   return content::ZoomLevelToZoomFactor(level);
 }
 
+void WebContents::SetZoomFactorIfNeeded(const GURL& url) {
+  if (zoom_factor_ == content::kMinimumZoomFactor)
+    return;
+
+  std::string host = net::GetHostOrSpecFromURL(url);
+  double zoom_factor = zoom_factor_;
+  auto it = host_zoom_factor_.find(host);
+  if (it != host_zoom_factor_.end())
+    zoom_factor = it->second;
+  auto level = content::ZoomFactorToZoomLevel(zoom_factor);
+  if (content::ZoomValuesEqual(level, GetZoomLevel()))
+    return;
+
+  SetZoomLevel(level);
+}
+
 v8::Local<v8::Value> WebContents::GetWebPreferences(v8::Isolate* isolate) {
   WebContentsPreferences* web_preferences =
       WebContentsPreferences::FromWebContents(web_contents());

atom/browser/api/atom_api_web_contents.h

@@ -349,11 +349,16 @@ class WebContents : public mate::TrackableObject<WebContents>,
                              const base::ListValue& args,
                              IPC::Message* message);
 
+  // Called after committing a navigation, to set the zoom
+  // factor.
+  void SetZoomFactorIfNeeded(const GURL& url);
+
   v8::Global<v8::Value> session_;
   v8::Global<v8::Value> devtools_web_contents_;
   v8::Global<v8::Value> debugger_;
 
   std::unique_ptr<WebViewGuestDelegate> guest_delegate_;
+  std::map<std::string, double> host_zoom_factor_;
 
   // The host webcontents that may contain this webcontents.
   WebContents* embedder_;
@@ -370,6 +375,9 @@ class WebContents : public mate::TrackableObject<WebContents>,
   // Whether to enable devtools.
   bool enable_devtools_;
 
+  // Initial zoom factor.
+  double zoom_factor_;
+
   DISALLOW_COPY_AND_ASSIGN(WebContents);
 };
 

atom/browser/web_contents_preferences.cc

@@ -130,13 +130,6 @@ void WebContentsPreferences::AppendExtraCommandLineSwitches(
   if (web_preferences.GetString(options::kBackgroundColor, &color))
     command_line->AppendSwitchASCII(switches::kBackgroundColor, color);
 
-  // The zoom factor.
-  double zoom_factor = 1.0;
-  if (web_preferences.GetDouble(options::kZoomFactor, &zoom_factor) &&
-      zoom_factor != 1.0)
-    command_line->AppendSwitchASCII(switches::kZoomFactor,
-                                    base::DoubleToString(zoom_factor));
-
   // --guest-instance-id, which is used to identify guest WebContents.
   int guest_instance_id = 0;
   if (web_preferences.GetInteger(options::kGuestInstanceID, &guest_instance_id))

atom/renderer/atom_render_view_observer.cc

@@ -14,7 +14,6 @@
 #include "atom/common/api/event_emitter_caller.h"
 #include "atom/common/native_mate_converters/value_converter.h"
 #include "atom/common/node_includes.h"
-#include "atom/common/options_switches.h"
 #include "atom/renderer/atom_renderer_client.h"
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
@@ -117,17 +116,6 @@ void AtomRenderViewObserver::EmitIPCEvent(blink::WebFrame* frame,
 void AtomRenderViewObserver::DidCreateDocumentElement(
     blink::WebLocalFrame* frame) {
   document_created_ = true;
-
-  // Read --zoom-factor from command line.
-  std::string zoom_factor_str = base::CommandLine::ForCurrentProcess()->
-      GetSwitchValueASCII(switches::kZoomFactor);
-  if (zoom_factor_str.empty())
-    return;
-  double zoom_factor;
-  if (!base::StringToDouble(zoom_factor_str, &zoom_factor))
-    return;
-  double zoom_level = blink::WebView::zoomFactorToZoomLevel(zoom_factor);
-  frame->view()->setZoomLevel(zoom_level);
 }
 
 void AtomRenderViewObserver::DraggableRegionsChanged(blink::WebFrame* frame) {