Fix X11DesktopHandler::ActivateWindow on Unity for known user gestures

ui/views/widget/native_widget_mac.h

 // Copyright 2014 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_WIDGET_NATIVE_WIDGET_MAC_H_
 #define UI_VIEWS_WIDGET_NATIVE_WIDGET_MAC_H_
 
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/widget/native_widget_private.h"
 
@@ skipping 61 matching lines @@
   void StackBelow(gfx::NativeView native_view) override;
   void SetShape(gfx::NativeRegion shape) override;
   void Close() override;
   void CloseNow() override;
   void Show() override;
   void Hide() override;
   void ShowMaximizedWithBounds(const gfx::Rect& restored_bounds) override;
   void ShowWithWindowState(ui::WindowShowState state) override;
   bool IsVisible() const override;
   void Activate() override;
+  void ActivateForUserGesture() override;
   void Deactivate() override;
   bool IsActive() const override;
   void SetAlwaysOnTop(bool always_on_top) override;
   bool IsAlwaysOnTop() const override;
   void SetVisibleOnAllWorkspaces(bool always_visible) override;
   void Maximize() override;
   void Minimize() override;
   bool IsMaximized() const override;
   bool IsMinimized() const override;
   void Restore() override;
@@ skipping 41 matching lines @@
   scoped_ptr<BridgedNativeWidget> bridge_;
 
   Widget::InitParams::Ownership ownership_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeWidgetMac);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_NATIVE_WIDGET_MAC_H_