events: Update scroll and touch handlers to not return EventResult.

ui/base/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/base/events/event_dispatcher.h"
 #include "ui/base/events/event_handler.h"
 
 #include "ui/base/events/event.h"
 
 namespace ui {
 
 EventHandler::EventHandler() {
 }
 
 EventHandler::~EventHandler() {
   while (!dispatchers_.empty()) {
     EventDispatcher* dispatcher = dispatchers_.top();
     dispatchers_.pop();
     dispatcher->OnHandlerDestroyed(this);
   }
 }
 
 void EventHandler::OnEvent(Event* event) {
   ui::EventResult result = ui::ER_UNHANDLED;
   if (event->IsKeyEvent())
     result = OnKeyEvent(static_cast<KeyEvent*>(event));
   else if (event->IsMouseEvent())
     result = OnMouseEvent(static_cast<MouseEvent*>(event));
   else if (event->IsScrollEvent())
-    result = OnScrollEvent(static_cast<ScrollEvent*>(event));
+    OnScrollEvent(static_cast<ScrollEvent*>(event));
   else if (event->IsTouchEvent())
-    result = OnTouchEvent(static_cast<TouchEvent*>(event));
+    OnTouchEvent(static_cast<TouchEvent*>(event));
   else if (event->IsGestureEvent())
     OnGestureEvent(static_cast<GestureEvent*>(event));
 
   if (result & ui::ER_CONSUMED)
     event->StopPropagation();
   if (result & ui::ER_HANDLED)
     event->SetHandled();
 }
 
 EventResult EventHandler::OnKeyEvent(KeyEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
 EventResult EventHandler::OnMouseEvent(MouseEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-EventResult EventHandler::OnScrollEvent(ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
+void EventHandler::OnScrollEvent(ScrollEvent* event) {
 }
 
-EventResult EventHandler::OnTouchEvent(TouchEvent* event) {
-  return ui::ER_UNHANDLED;
+void EventHandler::OnTouchEvent(TouchEvent* event) {
 }
 
 void EventHandler::OnGestureEvent(GestureEvent* event) {
 }
 
 }  // namespace ui