Fix X11DesktopHandler::ActivateWindow on Unity for known user gestures

ui/views/widget/native_widget_mac.mm

 // 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.
 
 #include "ui/views/widget/native_widget_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_nsobject.h"
@@ skipping 356 matching lines @@
   return bridge_ && bridge_->window_visible();
 }
 
 void NativeWidgetMac::Activate() {
   if (!bridge_)
     return;
 
   bridge_->SetVisibilityState(BridgedNativeWidget::SHOW_AND_ACTIVATE_WINDOW);
 }
 
+void NativeWidgetMac::ActivateForUserGesture() {
+  Activate();
+}
+
 void NativeWidgetMac::Deactivate() {
   NOTIMPLEMENTED();
 }
 
 bool NativeWidgetMac::IsActive() const {
   return [GetNativeWindow() isKeyWindow];
 }
 
 void NativeWidgetMac::SetAlwaysOnTop(bool always_on_top) {
   gfx::SetNSWindowAlwaysOnTop(GetNativeWindow(), always_on_top);
@@ skipping 251 matching lines @@
 }
 
 // static
 gfx::FontList NativeWidgetPrivate::GetWindowTitleFontList() {
   NOTIMPLEMENTED();
   return gfx::FontList();
 }
 
 }  // namespace internal
 }  // namespace views