android webview: Keep zoom methods synchronous

content/browser/android/synchronous_compositor_host.h

 // Copyright 2015 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_SYNCHRONOUS_COMPOSITOR_HOST_H_
 #define CONTENT_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 29 matching lines @@
       const gfx::Rect& clip,
       const gfx::Rect& viewport_rect_for_tile_priority,
       const gfx::Transform& transform_for_tile_priority) override;
   bool DemandDrawSw(SkCanvas* canvas) override;
   void ReturnResources(uint32_t output_surface_id,
                        const cc::CompositorFrameAck& frame_ack) override;
   void SetMemoryPolicy(size_t bytes_limit) override;
   void DidChangeRootLayerScrollOffset(
       const gfx::ScrollOffset& root_offset) override;
   void SetIsActive(bool is_active) override;
+  void SynchronizeWithRenderer() override;
   void OnComputeScroll(base::TimeTicks animation_time) override;
 
   // SynchronousCompositorBase overrides.
   InputEventAckState HandleInputEvent(
       const blink::WebInputEvent& input_event) override;
   void DidOverscroll(const DidOverscrollParams& over_scroll_params) override;
   void BeginFrame(const cc::BeginFrameArgs& args) override;
   bool OnMessageReceived(const IPC::Message& message) override;
   void DidBecomeCurrent() override;
 
@@ skipping 44 matching lines @@
   bool need_begin_frame_;
   uint32_t did_activate_pending_tree_count_;
 
   base::WeakPtrFactory<SynchronousCompositorHost> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(SynchronousCompositorHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_HOST_H_