Refactor how surfaces are acquired for GPU compositing.

chrome/browser/renderer_host/render_widget_host_view.h

Index: chrome/browser/renderer_host/render_widget_host_view.h
diff --git a/chrome/browser/renderer_host/render_widget_host_view.h b/chrome/browser/renderer_host/render_widget_host_view.h
index d1b5c2f0ac58f6bde360e7ae80d972454097f7ea..3ed1df90c6db023c2263987affc5782fc923560a 100644
--- a/chrome/browser/renderer_host/render_widget_host_view.h
+++ b/chrome/browser/renderer_host/render_widget_host_view.h
@@ -258,11 +258,13 @@ class RenderWidgetHostView {
 #endif
 
 #if defined(OS_WIN)
-  virtual gfx::PluginWindowHandle GetCompositorHostWindow() = 0;
   virtual void WillWmDestroy() = 0;
   virtual void ShowCompositorHostWindow(bool show) = 0;
 #endif
 
+  virtual gfx::PluginWindowHandle AcquireCompositingSurface() = 0;
+  virtual void ReleaseCompositingSurface(gfx::PluginWindowHandle surface) = 0;
+
   // Toggles visual muting of the render view area. This is on when a
   // constrained window is showing, for example. |color| is the shade of
   // the overlay that covers the render view. If |animate| is true, the overlay