Implement TOGGLE_EXPANSION action for the ARC notifications.

ui/arc/notification/arc_notification_item.cc

 // Copyright 2016 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/arc/notification/arc_notification_item.h"
 
 #include <algorithm>
 #include <utility>
 #include <vector>
 
@@ skipping 261 matching lines @@
 }
 
 void ArcNotificationItem::OpenSettings() {
   manager_->OpenNotificationSettings(notification_key_);
 }
 
 bool ArcNotificationItem::IsOpeningSettingsSupported() const {
   return manager_->IsOpeningSettingsSupported();
 }
 
+void ArcNotificationItem::ToggleExpansion() {
+  manager_->SendNotificationToggleExpansionOnChrome(notification_key_);
+}
+
 // Converts from Android notification priority to Chrome notification priority.
 // On Android, PRIORITY_DEFAULT does not pop up, so this maps PRIORITY_DEFAULT
 // to Chrome's -1 to adapt that behavior. Also, this maps PRIORITY_LOW and _HIGH
 // to -2 and 0 respectively to adjust the value with keeping the order among
 // _LOW, _DEFAULT and _HIGH.
 // static
 int ArcNotificationItem::ConvertAndroidPriority(int android_priority) {
   switch (android_priority) {
     case -2:  // PRIORITY_MIN
     case -1:  // PRIORITY_LOW
@@ skipping 41 matching lines @@
 
 void ArcNotificationItem::OnImageDecoded(const SkBitmap& bitmap) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   gfx::Image image = gfx::Image::CreateFrom1xBitmap(bitmap);
   notification_->set_icon(image);
   AddToMessageCenter();
 }
 
 }  // namespace arc