Remove Sync JS generic request/reply framework

sync/js/js_controller.h

Index: sync/js/js_controller.h
diff --git a/sync/js/js_controller.h b/sync/js/js_controller.h
index 08432bf004e62a3f2063a082d8bc37da8c0f97e2..482c8c1eba672fbf06dea50fc0e2ab711c545bd0 100644
--- a/sync/js/js_controller.h
+++ b/sync/js/js_controller.h
@@ -13,9 +13,7 @@
 
 namespace syncer {
 
-class JsArgList;
 class JsEventHandler;
-class JsReplyHandler;
 template <typename T> class WeakHandle;
 
 // An interface for objects that JsEventHandlers directly interact
@@ -36,12 +34,6 @@ class SYNC_EXPORT JsController {
   // immediately stop receiving any JS events.
   virtual void RemoveJsEventHandler(JsEventHandler* event_handler) = 0;
 
-  // Processes a JS message.  The reply (if any) will be sent to
-  // |reply_handler| if it is initialized.
-  virtual void ProcessJsMessage(
-      const std::string& name, const JsArgList& args,
-      const WeakHandle<JsReplyHandler>& reply_handler) = 0;
-
  protected:
   virtual ~JsController() {}
 };