Set an initial background for RenderFrameHosts during commit.

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <utility>
@@ skipping 4064 matching lines @@
     observer.RenderViewHostChanged(old_host, new_host);
 
   // Ensure that the associated embedder gets cleared after a RenderViewHost
   // gets swapped, so we don't reuse the same embedder next time a
   // RenderViewHost is attached to this WebContents.
   RemoveBrowserPluginEmbedder();
 }
 
 void WebContentsImpl::NotifyFrameSwapped(RenderFrameHost* old_host,
                                          RenderFrameHost* new_host) {
-  // Copies the background color from an old WebContents to a new one that
-  // replaces it on the screen. This allows the new WebContents to use the
-  // old one's background color as the starting background color, before having
-  // loaded any contents. As a result, we avoid flashing white when navigating
-  // from a site whith a dark background to another site with a dark background.
-  if (old_host && new_host) {
-    RenderWidgetHostView* old_view = old_host->GetView();
-    RenderWidgetHostView* new_view = new_host->GetView();
-    if (old_view && new_view)
-      new_view->SetBackgroundColor(old_view->background_color());
-  }
-
   for (auto& observer : observers_)
     observer.RenderFrameHostChanged(old_host, new_host);
 }
 
+void WebContentsImpl::NotifyInitialBackground(SkColor old_background,
+                                              RenderFrameHost* new_host) {
+  // This code copies the background color from an old WebContents to a new one
+  // that replaces it on the screen. This allows the new WebContents to use the
+  // old one's background color as the starting background color, before having
+  // loaded any contents. As a result, we avoid flashing white when navigating
+  // from a site whith a dark background to another site with a dark background.
+  if (new_host) {
+    RenderWidgetHostView* new_view = new_host->GetView();
+    if (new_view) {

[nasko, 2017/03/08 22:54:20]

nit: No need for {} on one line if statements.

+      new_view->SetBackgroundColor(old_background);
+    }
+  }
+}
+
 // TODO(avi): Remove this entire function because this notification is already
 // covered by two observer functions. http://crbug.com/170921
 void WebContentsImpl::NotifyDisconnected() {
   if (!notify_disconnection_)
     return;
 
   notify_disconnection_ = false;
   NotificationService::current()->Notify(
       NOTIFICATION_WEB_CONTENTS_DISCONNECTED,
       Source<WebContents>(this),
@@ skipping 1308 matching lines @@
     RenderViewHost* render_view_host = RenderViewHost::From(render_widget_host);
     if (!render_view_host)
       continue;
     render_view_host_set.insert(render_view_host);
   }
   for (RenderViewHost* render_view_host : render_view_host_set)
     render_view_host->OnWebkitPreferencesChanged();
 }
 
 }  // namespace content