Use black for resize gutter in tab fullscreen mode.

content/browser/renderer_host/delegated_frame_host.h

 // Copyright 2014 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_DELEGATED_FRAME_HOST_H_
 #define CONTENT_BROWSER_RENDERER_HOST_DELEGATED_FRAME_HOST_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 37 matching lines @@
 class RenderWidgetHostImpl;
 class ResizeLock;
 
 // The DelegatedFrameHostClient is the interface from the DelegatedFrameHost,
 // which manages delegated frames, and the ui::Compositor being used to
 // display them.
 class CONTENT_EXPORT DelegatedFrameHostClient {
  public:
   virtual ui::Layer* DelegatedFrameHostGetLayer() const = 0;
   virtual bool DelegatedFrameHostIsVisible() const = 0;
+
+  // The callee can change the value of *color to modify what color the resize
+  // gutters are drawn with.
+  virtual void DelegatedFrameHostOverrideGutterColor(SkColor* color) const = 0;
   virtual gfx::Size DelegatedFrameHostDesiredSizeInDIP() const = 0;
 
   virtual bool DelegatedFrameCanCreateResizeLock() const = 0;
   virtual std::unique_ptr<ResizeLock> DelegatedFrameHostCreateResizeLock(
       bool defer_compositor_lock) = 0;
   virtual void DelegatedFrameHostResizeLockWasReleased() = 0;
 
   virtual void DelegatedFrameHostSendCompositorSwapAck(
       int output_surface_id,
       const cc::CompositorFrameAck& ack) = 0;
@@ skipping 128 matching lines @@
 
   bool ShouldSkipFrame(gfx::Size size_in_dip) const;
 
   // Lazily grab a resize lock if the aura window size doesn't match the current
   // frame size, to give time to the renderer.
   void MaybeCreateResizeLock();
 
   // Checks if the resize lock can be released because we received an new frame.
   void CheckResizeLock();
 
+  SkColor GetGutterColor() const;
+
   // Update the layers for the resize gutters to the right and bottom of the
   // surface layer.
   void UpdateGutters();
 
   // Called after async thumbnailer task completes.  Scales and crops the result
   // of the copy.
   static void CopyFromCompositingSurfaceHasResultForVideo(
       base::WeakPtr<DelegatedFrameHost> rwhva,
       scoped_refptr<OwnedMailbox> subscriber_texture,
       scoped_refptr<media::VideoFrame> video_frame,
@@ skipping 101 matching lines @@
   std::unique_ptr<content::ReadbackYUVInterface> yuv_readback_pipeline_;
 
   std::unique_ptr<DelegatedFrameEvictor> delegated_frame_evictor_;
 
   cc::BeginFrameSource* begin_frame_source_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_DELEGATED_FRAME_HOST_H_