Fix touchpad zoom on touchscreen Windows devices.

ui/views/win/hwnd_message_handler.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_H_
 #define UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_
 
 #include <windows.h>
 
 #include <stddef.h>
@@ skipping 588 matching lines @@
 
   // Copy of custom window region specified via SetRegion(), if any.
   base::win::ScopedRegion custom_window_region_;
 
   // If > 0 indicates a menu is running (we're showing a native menu).
   int menu_depth_;
 
   // Generates touch-ids for touch-events.
   ui::SequentialIDGenerator id_generator_;
 
-  // Indicates if the window needs the WS_VSCROLL and WS_HSCROLL styles.
-  bool needs_scroll_styles_;
-
   // Set to true if we are in the context of a sizing operation.
   bool in_size_loop_;
 
   // Stores a pointer to the WindowEventTarget interface implemented by this
   // class. Allows callers to retrieve the interface pointer.
   std::unique_ptr<ui::ViewProp> prop_window_target_;
 
   // Number of active touch down contexts. This is incremented on touch down
   // events and decremented later using a delayed task.
   // We need this to ignore WM_MOUSEACTIVATE messages generated in response to
@@ skipping 62 matching lines @@
 
   // The factory used with BEGIN_SAFE_MSG_MAP_EX.
   base::WeakPtrFactory<HWNDMessageHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HWNDMessageHandler);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_