Introduce painted-device-scale-factor and use it when --enable-use-zoom-for-dsf is specified.

content/renderer/render_view_impl.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_RENDERER_RENDER_VIEW_IMPL_H_
 #define CONTENT_RENDERER_RENDER_VIEW_IMPL_H_
 
 #include <deque>
 #include <map>
 #include <set>
@@ skipping 744 matching lines @@
     navigation_gesture_ = gesture;
   }
 
   // Platform specific theme preferences if any are updated here.
 #if defined(OS_WIN)
   void UpdateThemePrefs();
 #else
   void UpdateThemePrefs() {}
 #endif
 
+  void UpdateDeviceScaleFactor();
+
   // ---------------------------------------------------------------------------
   // ADDING NEW FUNCTIONS? Please keep private functions alphabetized and put
   // it in the same order in the .cc file as it was in the header.
   // ---------------------------------------------------------------------------
 
   // Settings ------------------------------------------------------------------
 
   WebPreferences webkit_preferences_;
   RendererPreferences renderer_preferences_;
 
@@ skipping 246 matching lines @@
   // use the Observer interface to filter IPC messages and receive frame change
   // notifications.
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_VIEW_IMPL_H_