compositor-worker: Refactor CompositorWorkerManager

third_party/WebKit/public/platform/Platform.h

Index: third_party/WebKit/public/platform/Platform.h
diff --git a/third_party/WebKit/public/platform/Platform.h b/third_party/WebKit/public/platform/Platform.h
index 851d68f7a7a2fe8e3bf54af77b68a9ceb64fd6ac..1703be68b1f34e2408953a601ff131018099bc67 100644
--- a/third_party/WebKit/public/platform/Platform.h
+++ b/third_party/WebKit/public/platform/Platform.h
@@ -434,6 +434,10 @@ public:
     // Returns an interface to the main thread. Can be null if blink was initialized on a thread without a message loop.
     BLINK_PLATFORM_EXPORT WebThread* mainThread() const;
 
+    // Returns an interface to the compositor thread. This can be null if the
+    // renderer was created with threaded rendering desabled.
+    virtual WebThread* compositorThread() const { return 0; }
+
     // Vibration -----------------------------------------------------------
 
     // Starts a vibration for the given duration in milliseconds. If there is currently an active