Rewire Android WebView's compositor changed signal.

content/public/browser/android/synchronous_compositor_client.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_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_CLIENT_H_
 #define CONTENT_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_CLIENT_H_
 
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "ui/gfx/geometry/size_f.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 
 namespace content {
 
 class SynchronousCompositor;
 
 class SynchronousCompositorClient {
  public:
   // Indication to the client that |compositor| is now initialized on the
-  // compositor thread, and open for business.
-  virtual void DidInitializeCompositor(SynchronousCompositor* compositor) = 0;
+  // compositor thread, and open for business. |process_id| and |routing_id|
+  // belong to the RVH that owns the compositor.
+  virtual void DidInitializeCompositor(SynchronousCompositor* compositor,
+                                       int process_id,
+                                       int routing_id) = 0;
 
   // Indication to the client that |compositor| is going out of scope, and
   // must not be accessed within or after this call.
   // NOTE if the client goes away before the compositor it must call
   // SynchronousCompositor::SetClient(nullptr) to release the back pointer.
-  virtual void DidDestroyCompositor(SynchronousCompositor* compositor) = 0;
-
-  // Indication to the client that |compositor| just became the current one.
-  // The compositor has to be initialized first. An initialized compositor may
-  // not become current immediately.
-  virtual void DidBecomeCurrent(SynchronousCompositor* compositor) = 0;
+  virtual void DidDestroyCompositor(SynchronousCompositor* compositor,
+                                    int process_id,
+                                    int routing_id) = 0;
 
   // See LayerScrollOffsetDelegate for details.
   virtual void UpdateRootLayerState(const gfx::Vector2dF& total_scroll_offset,
                                     const gfx::Vector2dF& max_scroll_offset,
                                     const gfx::SizeF& scrollable_size,
                                     float page_scale_factor,
                                     float min_page_scale_factor,
                                     float max_page_scale_factor) = 0;
 
   virtual void DidOverscroll(const gfx::Vector2dF& accumulated_overscroll,
                              const gfx::Vector2dF& latest_overscroll_delta,
                              const gfx::Vector2dF& current_fling_velocity) = 0;
 
   virtual void PostInvalidate() = 0;
 
   virtual void DidUpdateContent() = 0;
 
  protected:
   SynchronousCompositorClient() {}
   virtual ~SynchronousCompositorClient() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SynchronousCompositorClient);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_CLIENT_H_