Maintain minimal error response.

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 <IOSurface/IOSurfaceAPI.h>
 #include <list>
@@ skipping 298 matching lines @@
   void Destroy() override;
   void SetTooltipText(const base::string16& tooltip_text) override;
   void SelectionChanged(const base::string16& text,
                         size_t offset,
                         const gfx::Range& range) override;
   void SelectionBoundsChanged(
       const ViewHostMsg_SelectionBounds_Params& params) override;
   void CopyFromCompositingSurface(const gfx::Rect& src_subrect,
                                   const gfx::Size& dst_size,
                                   ReadbackRequestCallback& callback,
-                                  SkColorType color_type) override;
+                                  SkColorType preferred_color_type) override;
   void CopyFromCompositingSurfaceToVideoFrame(
       const gfx::Rect& src_subrect,
       const scoped_refptr<media::VideoFrame>& target,
       const base::Callback<void(bool)>& callback) override;
   bool CanCopyToVideoFrame() const override;
   bool CanSubscribeFrame() const override;
   void BeginFrameSubscription(
       scoped_ptr<RenderWidgetHostViewFrameSubscriber> subscriber) override;
   void EndFrameSubscription() override;
   void OnSwapCompositorFrame(uint32 output_surface_id,
@@ skipping 11 matching lines @@
   gfx::GLSurfaceHandle GetCompositingSurface() override;
 
   bool LockMouse() override;
   void UnlockMouse() override;
   void WheelEventAck(const blink::WebMouseWheelEvent& event,
                      InputEventAckState ack_result) override;
 
   // IPC::Sender implementation.
   bool Send(IPC::Message* message) override;
 
-  SkColorType PreferredReadbackFormat() override;
-
   // gfx::DisplayObserver implementation.
   void OnDisplayAdded(const gfx::Display& new_display) override;
   void OnDisplayRemoved(const gfx::Display& old_display) override;
   void OnDisplayMetricsChanged(const gfx::Display& display,
                                uint32_t metrics) override;
 
   // Forwards the mouse event to the renderer.
   void ForwardMouseEvent(const blink::WebMouseEvent& event);
 
   void KillSelf();
@@ skipping 224 matching lines @@
 
   // Factory used to safely scope delayed calls to ShutdownHost().
   base::WeakPtrFactory<RenderWidgetHostViewMac> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_