Rewire Android WebView's compositor changed signal.

content/browser/android/synchronous_compositor_host.h

Index: content/browser/android/synchronous_compositor_host.h
diff --git a/content/browser/android/synchronous_compositor_host.h b/content/browser/android/synchronous_compositor_host.h
index b30e8f87741669fb869c0926278bfcdc8ab0ae07..9f7afe04fc569dfbe4addd291c42f2852780436b 100644
--- a/content/browser/android/synchronous_compositor_host.h
+++ b/content/browser/android/synchronous_compositor_host.h
@@ -71,7 +71,6 @@ class SynchronousCompositorHost : public SynchronousCompositor {
   void DidOverscroll(const DidOverscrollParams& over_scroll_params);
   void BeginFrame(const cc::BeginFrameArgs& args);
   bool OnMessageReceived(const IPC::Message& message);
-  void DidBecomeCurrent();
 
  private:
   class ScopedSendZeroMemory;
@@ -100,6 +99,7 @@ class SynchronousCompositorHost : public SynchronousCompositor {
   SynchronousCompositorClient* const client_;
   const scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
   const int routing_id_;
+  const int process_id_;
   IPC::Sender* const sender_;
   const bool async_input_;
   const bool use_in_process_zero_copy_software_draw_;