Fix use after free when handling async touch events

ui/views/win/hwnd_message_handler_delegate.h

 // 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.
 
 #ifndef UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_DELEGATE_H_
 #define UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_DELEGATE_H_
 
 #include "ui/views/views_export.h"
 
 namespace gfx {
@@ skipping 167 matching lines @@
   virtual bool HandleMouseEvent(const ui::MouseEvent& event) = 0;
 
   // Called when a translated key event is received (i.e. post IME translation.)
   // Returns true if the event was handled by the delegate.
   virtual bool HandleKeyEvent(const ui::KeyEvent& event) = 0;
 
   // Called when an untranslated key event is received (i.e. pre-IME
   // translation). Returns true if the event was sent to the input method.
   virtual bool HandleUntranslatedKeyEvent(const ui::KeyEvent& event) = 0;
 
-  // Called when a touch event is received. Returns true if the event was
-  // handled by the delegate.
-  virtual bool HandleTouchEvent(const ui::TouchEvent& event) = 0;
+  // Called when a touch event is received.
+  virtual void HandleTouchEvent(const ui::TouchEvent& event) = 0;
 
   // Called when an IME message needs to be processed by the delegate. Returns
   // true if the event was handled and no default processing should be
   // performed.
   virtual bool HandleIMEMessage(UINT message,
                                 WPARAM w_param,
                                 LPARAM l_param,
                                 LRESULT* result) = 0;
 
   // Called when the system input language changes.
@@ skipping 34 matching lines @@
                              WPARAM w_param,
                              LPARAM l_param) = 0;
 
  protected:
   virtual ~HWNDMessageHandlerDelegate() {}
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_DELEGATE_H_