Enable browser process hit testing on Android

ui/android/delegated_frame_host_android.h

 // Copyright 2016 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 UI_ANDROID_DELEGATED_FRAME_HOST_ANDROID_H_
 #define UI_ANDROID_DELEGATED_FRAME_HOST_ANDROID_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "cc/output/copy_output_request.h"
@@ skipping 50 matching lines @@
       const gfx::Rect& src_subrect_in_pixel,
       cc::CopyOutputRequest::CopyOutputRequestCallback result_callback);
 
   void CompositorFrameSinkChanged();
 
   // Called when this DFH is attached/detached from a parent browser compositor
   // and needs to be attached to the surface hierarchy.
   void AttachToCompositor(WindowAndroidCompositor* compositor);
   void DetachFromCompositor();
 
+  // Returns the ID for the current Surface.
+  cc::SurfaceId SurfaceId() const;
+
  private:
   // cc::CompositorFrameSinkSupportClient implementation.
   void DidReceiveCompositorFrameAck() override;
   void OnBeginFrame(const cc::BeginFrameArgs& args) override;
   void ReclaimResources(const cc::ReturnedResourceArray& resources) override;
   void WillDrawSurface(const cc::LocalSurfaceId& local_surface_id,
                        const gfx::Rect& damage_rect) override;
 
   // cc::ExternalBeginFrameSourceClient implementation.
   void OnNeedsBeginFrames(bool needs_begin_frames) override;
@@ skipping 29 matching lines @@
   std::unique_ptr<FrameData> current_frame_;
 
   scoped_refptr<cc::SurfaceLayer> content_layer_;
 
   DISALLOW_COPY_AND_ASSIGN(DelegatedFrameHostAndroid);
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_DELEGATED_FRAME_HOST_ANDROID_H_