Fix gesture event handling in MenuButton

ui/views/controls/button/menu_button.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/views/controls/button/menu_button.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "grit/ui_resources.h"
 #include "grit/ui_strings.h"
 #include "ui/accessibility/ax_view_state.h"
@@ skipping 184 matching lines @@
 // BaseButton::OnMouseExited will get the event and will set the button's state
 // to STATE_NORMAL instead of keeping the state BM_PUSHED. This, in turn, will
 // cause the button to appear depressed while the menu is displayed.
 void MenuButton::OnMouseExited(const ui::MouseEvent& event) {
   if ((state_ != STATE_DISABLED) && (!menu_visible_) && (!InDrag())) {
     SetState(STATE_NORMAL);
   }
 }
 
 void MenuButton::OnGestureEvent(ui::GestureEvent* event) {
-  if (state() != STATE_DISABLED && event->type() == ui::ET_GESTURE_TAP) {
-    if (Activate())
-      event->StopPropagation();
+  if (state() != STATE_DISABLED && event->type() == ui::ET_GESTURE_TAP &&
+      !Activate()) {
+    // When |Activate()| returns |false|, it means that a menu is shown and
+    // has handled the gesture event. So, there is no need to further process
+    // the gesture event here.
     return;
   }
   TextButton::OnGestureEvent(event);
 }
 
 bool MenuButton::OnKeyPressed(const ui::KeyEvent& event) {
   switch (event.key_code()) {
     case ui::VKEY_SPACE:
       // Alt-space on windows should show the window menu.
       if (event.IsAltDown())
@@ skipping 49 matching lines @@
   if (!GetWidget()) {
     NOTREACHED();
     return 0;
   }
 
   gfx::Rect monitor_bounds = GetWidget()->GetWorkAreaBoundsInScreen();
   return monitor_bounds.right() - 1;
 }
 
 }  // namespace views