Use correct device scale factors in Aura

content/browser/renderer_host/render_widget_host_view_aura.h

Index: content/browser/renderer_host/render_widget_host_view_aura.h
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.h b/content/browser/renderer_host/render_widget_host_view_aura.h
index 10b1a7192b761326d09aa438a8773939b48737c4..1b49553e84e70e87fd8564853239cd8e4323f920 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.h
+++ b/content/browser/renderer_host/render_widget_host_view_aura.h
@@ -457,10 +457,12 @@ class RenderWidgetHostViewAura
   // The common entry point for full buffer updates from renderer
   // and GPU process.
   void BuffersSwapped(const gfx::Size& size,
+                      float surface_scale_factor,
                       const std::string& mailbox_name,
                       const BufferPresentedCallback& ack_callback);
 
   bool SwapBuffersPrepare(const gfx::Rect& surface_rect,
+                          float surface_scale_factor,
                           const gfx::Rect& damage_rect,
                           const std::string& mailbox_name,
                           const BufferPresentedCallback& ack_callback);
@@ -572,6 +574,7 @@ class RenderWidgetHostViewAura
   // Used to determine when the skipped_damage_ needs to be reset due to
   // size changes between front- and backbuffer.
   gfx::Size last_swapped_surface_size_;
+  float last_swapped_surface_scale_factor_;
 
   int pending_thumbnail_tasks_;