Move preferred scrollbar style preference change listening from renderer to browser, 2 of 3.

content/renderer/render_thread_impl.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_RENDERER_RENDER_THREAD_IMPL_H_
 #define CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/memory/memory_pressure_listener.h"
 #include "base/metrics/user_metrics_action.h"
 #include "base/observer_list.h"
 #include "base/process/process_handle.h"
 #include "base/strings/string16.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
 #include "content/child/child_thread.h"
 #include "content/common/content_export.h"
 #include "content/common/gpu/client/gpu_channel_host.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/renderer/media/renderer_gpu_video_accelerator_factories.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ui/gfx/native_widget_types.h"
 
+#if defined(OS_MACOSX)
+#include "third_party/WebKit/public/web/mac/WebScrollbarTheme.h"
+#endif
+
 class GrContext;
 class SkBitmap;
 struct ViewMsg_New_Params;
 
 namespace blink {
 class WebGamepads;
 class WebGraphicsContext3D;
 class WebMediaStreamCenter;
 class WebMediaStreamCenterClient;
 }
@@ skipping 351 matching lines @@
   void OnSetRendererProcessID(base::ProcessId process_id);
   void OnMemoryPressure(
       base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);
 #if defined(OS_ANDROID)
   void OnSetWebKitSharedTimersSuspended(bool suspend);
 #endif
 #if defined(OS_MACOSX)
   void OnUpdateScrollbarTheme(float initial_button_delay,
                               float autoscroll_button_delay,
                               bool jump_on_track_click,
+                              blink::ScrollerStyle preferred_scroller_style,
                               bool redraw);
 #endif
 
   void IdleHandlerInForegroundTab();
 
   scoped_ptr<WebGraphicsContext3DCommandBufferImpl> CreateOffscreenContext3d();
 
   // These objects live solely on the render thread.
   scoped_ptr<AppCacheDispatcher> appcache_dispatcher_;
   scoped_ptr<DomStorageDispatcher> dom_storage_dispatcher_;
@@ skipping 97 matching lines @@
   // multiple threads. Current allocation mechanism for IOSurface
   // backed GpuMemoryBuffers prevent this. crbug.com/325045
   base::ThreadChecker allocate_gpu_memory_buffer_thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_THREAD_IMPL_H_