Make IsTriggerableEvent take Event objects and use it to verify whether tap events should trigger.

ui/views/controls/button/button_dropdown.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/button_dropdown.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
@@ skipping 105 matching lines @@
   SetState(BS_HOT);
 }
 
 void ButtonDropDown::GetAccessibleState(ui::AccessibleViewState* state) {
   CustomButton::GetAccessibleState(state);
   state->role = ui::AccessibilityTypes::ROLE_BUTTONDROPDOWN;
   state->default_action = l10n_util::GetStringUTF16(IDS_APP_ACCACTION_PRESS);
   state->state = ui::AccessibilityTypes::STATE_HASPOPUP;
 }
 
-bool ButtonDropDown::ShouldEnterPushedState(const MouseEvent& event) {
-  // Enter PUSHED state on press with Left or Right mouse button. Remain
-  // in this state while the context menu is open.
-  return ((ui::EF_LEFT_MOUSE_BUTTON |
-      ui::EF_RIGHT_MOUSE_BUTTON) & event.flags()) != 0;
+bool ButtonDropDown::ShouldEnterPushedState(const Event& event) {
+  // Enter PUSHED state on press with Left or Right mouse button or on taps.
+  // Remain in this state while the context menu is open.
+  return event.type() == ui::ET_GESTURE_TAP ||
+         event.type() == ui::ET_GESTURE_TAP_DOWN ||
+         (event.IsMouseEvent() && ((ui::EF_LEFT_MOUSE_BUTTON |
+             ui::EF_RIGHT_MOUSE_BUTTON) & event.flags()) != 0);
 }
 
 void ButtonDropDown::ShowDropDownMenu(gfx::NativeView window) {
   gfx::Rect lb = GetLocalBounds();
 
   // Both the menu position and the menu anchor type change if the UI layout
   // is right-to-left.
   gfx::Point menu_position(lb.origin());
   menu_position.Offset(0, lb.height() - 1);
   if (base::i18n::IsRTL())
@@ skipping 44 matching lines @@
     SetState(BS_NORMAL);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 //
 // ButtonDropDown - Accessibility
 //
 ////////////////////////////////////////////////////////////////////////////////
 
 }  // namespace views