Do not dynamically call setLayer on RenderWidgetHostViewCocoa

content/browser/renderer_host/render_widget_host_view_mac.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_MAC_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <list>
 #include <map>
@@ skipping 423 matching lines @@
   // value returns true for is_null() if we are not recording whiteout times.
   base::TimeTicks whiteout_start_time_;
 
   // The time it took after this view was selected for it to be fully painted.
   base::TimeTicks web_contents_switch_paint_time_;
 
   // Current text input type.
   ui::TextInputType text_input_type_;
   bool can_compose_inline_;
 
-  // The background CoreAnimation layer used before compositing nor software
-  // compositing has been enabled, and when the compositing or software
-  // compositing surface has been evicted.
+  // The background CoreAnimation layer which is hosted by |cocoa_view_|.
+  // The compositing or software layers will be added as sublayers to this.
   base::scoped_nsobject<CALayer> background_layer_;
 
-  // The CoreAnimation layer for software compositing. Note that at most one of
-  // |software_layer_| and |compositing_iosurface_layer_| may be non-NULL.
+  // The CoreAnimation layer for software compositing. This should be NULL
+  // when software compositing is not in use.
   base::scoped_nsobject<SoftwareLayer> software_layer_;
 
   // Accelerated compositing structures. These may be dynamically created and
   // destroyed together in Create/DestroyCompositedIOSurfaceAndLayer.
   base::scoped_nsobject<CompositingIOSurfaceLayer> compositing_iosurface_layer_;
   scoped_ptr<CompositingIOSurfaceMac> compositing_iosurface_;
   scoped_refptr<CompositingIOSurfaceContext> compositing_iosurface_context_;
 
   // Timer used to dynamically transition the compositing layer in and out of
   // asynchronous mode.
@@ skipping 77 matching lines @@
   // deleted it will delete this out from under the caller.
   explicit RenderWidgetHostViewMac(RenderWidgetHost* widget);
 
   // Returns whether this render view is a popup (autocomplete window).
   bool IsPopup() const;
 
   // Shuts down the render_widget_host_.  This is a separate function so we can
   // invoke it from the message loop.
   void ShutdownHost();
 
-  void CreateSoftwareLayerAndDestroyCompositedLayer();
+  void CreateSoftwareLayer();
   void DestroySoftwareLayer();
 
   bool CreateCompositedIOSurface();
-  bool CreateCompositedLayerAndDestroySoftwareLayer();
+  bool CreateCompositedIOSurfaceLayer();
   enum DestroyContextBehavior {
     kLeaveContextBoundToView,
     kDestroyContext,
   };
+  void DestroyCompositedIOSurfaceLayer();
   void DestroyCompositedIOSurfaceAndLayer(DestroyContextBehavior
       destroy_context_behavior);
 
   // Unbind the GL context (if any) that is bound to |cocoa_view_|.
   void ClearBoundContextDrawable();
 
   // Called when a GPU SwapBuffers is received.
   void GotAcceleratedFrame();
 
   // Called when a software DIB is received.
@@ skipping 74 matching lines @@
   scoped_ptr<RenderWidgetHostViewFrameSubscriber> frame_subscriber_;
 
   base::WeakPtrFactory<RenderWidgetHostViewMac>
       software_frame_weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_