Propagate view background color when changing visible web contents.

content/browser/renderer_host/render_widget_host_view_base.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 72 matching lines @@
   float current_device_scale_factor() const {
     return current_device_scale_factor_;
   }
 
   // Returns the focused RenderWidgetHost inside this |view|'s RWH.
   RenderWidgetHostImpl* GetFocusedWidget() const;
 
   // RenderWidgetHostView implementation.
   RenderWidgetHost* GetRenderWidgetHost() const override;
   void SetBackgroundColor(SkColor color) override;
+  SkColor background_color() override;
   void SetBackgroundColorToDefault() final;
   bool GetBackgroundOpaque() override;
   ui::TextInputClient* GetTextInputClient() override;
   void WasUnOccluded() override {}
   void WasOccluded() override {}
   bool IsShowingContextMenu() const override;
   void SetShowingContextMenu(bool showing_menu) override;
   base::string16 GetSelectedText() override;
   bool IsMouseLocked() override;
   gfx::Size GetVisibleViewportSize() const override;
@@ skipping 396 matching lines @@
   base::ObserverList<RenderWidgetHostViewBaseObserver> observers_;
 
   base::WeakPtrFactory<RenderWidgetHostViewBase> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewBase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_