Use black for resize gutter in tab fullscreen mode.

content/browser/renderer_host/render_widget_host_view_aura.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_AURA_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_AURA_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 416 matching lines @@
 
   // Called after |window_| is parented to a WindowEventDispatcher.
   void AddedToRootWindow();
 
   // Called prior to removing |window_| from a WindowEventDispatcher.
   void RemovingFromRootWindow();
 
   // DelegatedFrameHostClient implementation.
   ui::Layer* DelegatedFrameHostGetLayer() const override;
   bool DelegatedFrameHostIsVisible() const override;
+  SkColor DelegatedFrameHostGetGutterColor(SkColor color) const override;
   gfx::Size DelegatedFrameHostDesiredSizeInDIP() const override;
   bool DelegatedFrameCanCreateResizeLock() const override;
   std::unique_ptr<ResizeLock> DelegatedFrameHostCreateResizeLock(
       bool defer_compositor_lock) override;
   void DelegatedFrameHostResizeLockWasReleased() override;
   void DelegatedFrameHostSendCompositorSwapAck(
       int output_surface_id,
       const cc::CompositorFrameAck& ack) override;
   void DelegatedFrameHostSendReclaimCompositorResources(
       int output_surface_id,
@@ skipping 225 matching lines @@
   bool disable_input_event_router_for_testing_;
 
   base::WeakPtrFactory<RenderWidgetHostViewAura> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewAura);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_AURA_H_