Make RootView::DispatchGestureEvent() non-virtual

ui/events/event_handler.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/events/event_handler.h"
 
 #include "ui/events/event.h"
 #include "ui/events/event_dispatcher.h"
 
 namespace ui {
 
 EventHandler::EventHandler() {
 }
 
 EventHandler::~EventHandler() {
   while (!dispatchers_.empty()) {
     EventDispatcher* dispatcher = dispatchers_.top();
     dispatchers_.pop();
     dispatcher->OnHandlerDestroyed(this);
   }
 }
 
 void EventHandler::OnEvent(Event* event) {
+  // TODO(tdanderson): Encapsulate static_casts in ui::Event for all
+  //                   event types.
   if (event->IsKeyEvent())
     OnKeyEvent(static_cast<KeyEvent*>(event));
   else if (event->IsMouseEvent())
     OnMouseEvent(static_cast<MouseEvent*>(event));
   else if (event->IsScrollEvent())
     OnScrollEvent(static_cast<ScrollEvent*>(event));
   else if (event->IsTouchEvent())
     OnTouchEvent(static_cast<TouchEvent*>(event));
   else if (event->IsGestureEvent())
-    OnGestureEvent(static_cast<GestureEvent*>(event));
+    OnGestureEvent(event->AsGestureEvent());
   else if (event->type() == ET_CANCEL_MODE)
     OnCancelMode(static_cast<CancelModeEvent*>(event));
 }
 
 void EventHandler::OnKeyEvent(KeyEvent* event) {
 }
 
 void EventHandler::OnMouseEvent(MouseEvent* event) {
 }
 
 void EventHandler::OnScrollEvent(ScrollEvent* event) {
 }
 
 void EventHandler::OnTouchEvent(TouchEvent* event) {
 }
 
 void EventHandler::OnGestureEvent(GestureEvent* event) {
 }
 
 void EventHandler::OnCancelMode(CancelModeEvent* event) {
 }
 
 }  // namespace ui