Fixes bug where Env/RootWindow would cache the wrong button

ui/base/win/events_win.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 <windowsx.h>
 
 #include "ui/base/events.h"
 
 #include "base/logging.h"
 #include "base/time.h"
@@ skipping 206 matching lines @@
 
 KeyboardCode KeyboardCodeFromNative(const base::NativeEvent& native_event) {
   return KeyboardCodeForWindowsKeyCode(native_event.wParam);
 }
 
 bool IsMouseEvent(const base::NativeEvent& native_event) {
   return IsClientMouseEvent(native_event) ||
          IsNonClientMouseEvent(native_event);
 }
 
+int GetChangedMouseButtonFlagsFromNative(
+    const base::NativeEvent& native_event) {
+  // TODO(sky): implement me.
+  return 0;
+}
+
 int GetMouseWheelOffset(const base::NativeEvent& native_event) {
   DCHECK(native_event.message == WM_MOUSEWHEEL);
   return GET_WHEEL_DELTA_WPARAM(native_event.wParam);
 }
 
 int GetTouchId(const base::NativeEvent& xev) {
   NOTIMPLEMENTED();
   return 0;
 }
 
@@ skipping 81 matching lines @@
 // Windows emulates mouse messages for touch events.
 bool IsMouseEventFromTouch(UINT message) {
   return (message == WM_MOUSEMOVE ||
       message == WM_LBUTTONDOWN || message == WM_LBUTTONUP ||
       message == WM_RBUTTONDOWN || message == WM_RBUTTONUP) &&
       (GetMessageExtraInfo() & MOUSEEVENTF_FROMTOUCH) ==
       MOUSEEVENTF_FROMTOUCH;
 }
 
 }  // namespace ui