compositor-worker: Initialize CW machinery plumbing to compositor and fire CW rAF callbacks.

third_party/WebKit/public/web/WebView.h

Index: third_party/WebKit/public/web/WebView.h
diff --git a/third_party/WebKit/public/web/WebView.h b/third_party/WebKit/public/web/WebView.h
index 827a61ef1caad6b34af66d0bb997af9dec29f015..35af9e28e99885a6ad588ad7fee16b4902f3ce9c 100644
--- a/third_party/WebKit/public/web/WebView.h
+++ b/third_party/WebKit/public/web/WebView.h
@@ -44,6 +44,7 @@
 
 namespace blink {
 
+class CompositorProxyClient;
 class WebAXObject;
 class WebAutofillClient;
 class WebCompositedDisplayList;
@@ -480,6 +481,12 @@ public:
     // context's ability to deal with that failure gracefully can be tested.
     virtual void forceNextDrawingBufferCreationToFail() = 0;
 
+    // CompositorWorker -----------------------------------------------------
+
+    // Initializes the compositor worker machinery and ensures that it is
+    // plumbed to the compositor.
+    virtual CompositorProxyClient* createCompositorProxyClient() = 0;

[jbroman, 2016/04/20 19:24:51]

This is not called outside of Source/web/ (AFIACT its only caller is
ChromeClientImpl), so it need to be part of the Blink public API. It can just be
a non-virtual method on WebViewImpl.

[flackr, 2016/04/25 14:06:28]

Good catch, this doesn't need to be virtual at all. Done.

+
 protected:
     ~WebView() {}
 };