Rewire Android WebView's compositor changed signal.

android_webview/native/aw_contents.cc

 // Copyright 2012 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.
 
 #include "android_webview/native/aw_contents.h"
 
 #include <limits>
 #include <utility>
 
 #include "android_webview/browser/aw_browser_context.h"
@@ skipping 154 matching lines @@
 AwBrowserPermissionRequestDelegate* AwBrowserPermissionRequestDelegate::FromID(
     int render_process_id, int render_frame_id) {
   AwContents* aw_contents = AwContents::FromWebContents(
       content::WebContents::FromRenderFrameHost(
           content::RenderFrameHost::FromID(render_process_id,
                                            render_frame_id)));
   return aw_contents;
 }
 
 AwContents::AwContents(std::unique_ptr<WebContents> web_contents)
-    : functor_(nullptr),
+    : content::WebContentsObserver(web_contents.get()),
+      functor_(nullptr),
       browser_view_renderer_(
           this,
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI)),
       web_contents_(std::move(web_contents)),
       renderer_manager_key_(GLViewRendererManager::GetInstance()->NullKey()) {
   base::subtle::NoBarrier_AtomicIncrement(&g_instance_count, 1);
   icon_helper_.reset(new IconHelper(web_contents_.get()));
   icon_helper_->SetListener(this);
   web_contents_->SetUserData(android_webview::kAwContentsUserDataKey,
                              new AwContentsUserData(this));
   browser_view_renderer_.RegisterWithWebContents(web_contents_.get());
+
+  CompositorID compositor_id;
+  if (web_contents_->GetRenderProcessHost() &&
+      web_contents_->GetRenderViewHost()) {
+    compositor_id.process_id = web_contents_->GetRenderProcessHost()->GetID();
+    compositor_id.routing_id = web_contents_->GetRoutingID();
+  }
+
+  browser_view_renderer_.SetActiveCompositorID(compositor_id);
   render_view_host_ext_.reset(
       new AwRenderViewHostExt(this, web_contents_.get()));
 
   permission_request_handler_.reset(
       new PermissionRequestHandler(this, web_contents_.get()));
 
   AwAutofillClient* autofill_manager_delegate =
       AwAutofillClient::FromWebContents(web_contents_.get());
   if (autofill_manager_delegate)
     InitAutofillIfNecessary(autofill_manager_delegate->GetSaveFormData());
@@ skipping 1084 matching lines @@
     JNIEnv* env,
     const JavaParamRef<jobject>& obj) {
   web_contents_->ResumeLoadingCreatedWebContents();
 }
 
 void SetShouldDownloadFavicons(JNIEnv* env,
                                const JavaParamRef<jclass>& jclazz) {
   g_should_download_favicons = true;
 }
 
+void AwContents::RenderViewHostChanged(content::RenderViewHost* old_host,
+                                       content::RenderViewHost* new_host) {
+  DCHECK(new_host);
+
+  int process_id = new_host->GetProcess()->GetID();
+  int routing_id = new_host->GetRoutingID();
+  // At this point, the current RVH may or may not contain a compositor. So
+  // compositor_ may be nullptr, in which case
+  // BrowserViewRenderer::DidInitializeCompositor() callback is time when the
+  // new compositor is constructed.
+  browser_view_renderer_.SetActiveCompositorID(
+      CompositorID(process_id, routing_id));
+}
+
 }  // namespace android_webview