Introduce AnimationWorkletProxyClient and necessary plumbing to get it in worklet messaging proxy.

third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp

Index: third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp
diff --git a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp
index 71fe8157ae0eaa9aec5ef823ab822fb9c884751e..2c01cd73fe28da475fa4dbfef23453a379843d49 100644
--- a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp
+++ b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp
@@ -47,14 +47,14 @@ CompositorWorkerGlobalScope::CompositorWorkerGlobalScope(
                         workerClients),
       m_executingAnimationFrameCallbacks(false),
       m_callbackCollection(this) {
-  CompositorProxyClient::from(clients())->setGlobalScope(this);
+  CompositorWorkerProxyClient::from(clients())->setGlobalScope(this);
 }
 
 CompositorWorkerGlobalScope::~CompositorWorkerGlobalScope() {}
 
 void CompositorWorkerGlobalScope::dispose() {
   WorkerGlobalScope::dispose();
-  CompositorProxyClient::from(clients())->dispose();
+  CompositorWorkerProxyClient::from(clients())->dispose();
 }
 
 DEFINE_TRACE(CompositorWorkerGlobalScope) {
@@ -85,7 +85,7 @@ int CompositorWorkerGlobalScope::requestAnimationFrame(
   const bool shouldSignal =
       !m_executingAnimationFrameCallbacks && m_callbackCollection.isEmpty();
   if (shouldSignal)
-    CompositorProxyClient::from(clients())->requestAnimationFrame();
+    CompositorWorkerProxyClient::from(clients())->requestAnimationFrame();
   return m_callbackCollection.registerCallback(callback);
 }