Refactor delegated scrolling in LayerImpl

content/browser/android/in_process/synchronous_compositor_impl.h

 // Copyright 2013 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_ANDROID_IN_PROCESS_SYNCHRONOUS_COMPOSITOR_IMPL_H_
 #define CONTENT_BROWSER_ANDROID_IN_PROCESS_SYNCHRONOUS_COMPOSITOR_IMPL_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 64 matching lines @@
 
   // LayerScrollOffsetDelegate
   gfx::ScrollOffset GetTotalScrollOffset() override;
   void UpdateRootLayerState(const gfx::ScrollOffset& total_scroll_offset,
                             const gfx::ScrollOffset& max_scroll_offset,
                             const gfx::SizeF& scrollable_size,
                             float page_scale_factor,
                             float min_page_scale_factor,
                             float max_page_scale_factor) override;
   bool IsExternalFlingActive() const override;
+  void SetBlockUpdates(bool block_updates) override;
 
   void SetInputHandler(cc::InputHandler* input_handler);
   void DidOverscroll(const DidOverscrollParams& params);
   void DidStopFlinging();
 
  private:
   friend class WebContentsUserData<SynchronousCompositorImpl>;
   friend class SynchronousCompositor;
   explicit SynchronousCompositorImpl(WebContents* contents);
   ~SynchronousCompositorImpl() override;
 
   void SetClient(SynchronousCompositorClient* compositor_client);
   void UpdateFrameMetaData(const cc::CompositorFrameMetadata& frame_info);
   void NotifyDidDestroyCompositorToClient();
   void DidActivatePendingTree();
   void DeliverMessages();
   bool CalledOnValidThread() const;
 
   SynchronousCompositorClient* compositor_client_;
   SynchronousCompositorOutputSurface* output_surface_;
   SynchronousCompositorExternalBeginFrameSource* begin_frame_source_;
   WebContents* contents_;
   const int routing_id_;
   cc::InputHandler* input_handler_;
   bool invoking_composite_;
+  bool block_updates_;

[aelias_OOO_until_Jul13, 2015/03/30 22:54:39]

Nobody ever reads this value, is there some other missing piece to this change?

Also, I don't really like the idea of a "block updates" boolean, we shouldn't
really need a bit of extra state just to maintain consistency on a single
thread.

[hush (inactive), 2015/03/30 23:00:44]

sorry I accidentally removed the usage in one of the patches. It should be used
by UpdateRootLayerState. I just added it back.
I will think about another way to achieve this.

 
   base::WeakPtrFactory<SynchronousCompositorImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SynchronousCompositorImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_IN_PROCESS_SYNCHRONOUS_COMPOSITOR_IMPL_H_