compositor-worker: Add CompositorProxyClient worker client of CompositorWorker.

third_party/WebKit/Source/web/ChromeClientImpl.cpp

Index: third_party/WebKit/Source/web/ChromeClientImpl.cpp
diff --git a/third_party/WebKit/Source/web/ChromeClientImpl.cpp b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
index ab5b0e7b38da10ede99bb915ea7f6405b1e21267..d86f4cc7c2c4de7e5d29cb8dbd61b3cac21637f5 100644
--- a/third_party/WebKit/Source/web/ChromeClientImpl.cpp
+++ b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
@@ -1073,6 +1073,11 @@ void ChromeClientImpl::didUpdateTopControls() const
     m_webView->didUpdateTopControls();
 }
 
+CompositorProxyClient* ChromeClientImpl::createCompositorProxyClient()
+{
+    return m_webView->createCompositorProxyClient();

[haraken, 2016/05/11 00:38:26]

Would you help me understand why you want to create the worker client via
ChromeClient?

Other WorkerClients are created in WebEmbeddedWorkerImpl::startWorkerThread.

+}
+
 void ChromeClientImpl::registerPopupOpeningObserver(PopupOpeningObserver* observer)
 {
     DCHECK(observer);