Close Chrome OS message center on back key

This CL has DummyView handle a back key event and close the Chrome OS
message center if it opens. This fix is for ag/112017890.

Note that DummyView handles key events only when no other ARC window
is focused.

ARC-side: ag/4779503
Chromium-side: crrev.com/1175709

Bug: b/112017890
Test: Ran atest
Change-Id: If0603bd68f2ad4f482521e7cf3e698edb934183f
Reviewed-on: https://chromium-review.googlesource.com/1175709Reviewed-by: Greg Kerr <kerrnel@chromium.org>
Reviewed-by: Eliot Courtney <edcourtney@chromium.org>
Commit-Queue: Yoshiki Iguchi <yoshiki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590044}

ash/message_center/arc_notification_manager_delegate_impl.cc

@@ -55,4 +55,20 @@ void ArcNotificationManagerDelegateImpl::ShowMessageCenter() {
   }
 }
 
+void ArcNotificationManagerDelegateImpl::HideMessageCenter() {
+  // Close the message center on all the displays.
+  for (auto* root_window_controller :
+       RootWindowController::root_window_controllers()) {
+    if (features::IsSystemTrayUnifiedEnabled()) {
+      root_window_controller->GetStatusAreaWidget()
+          ->unified_system_tray()
+          ->CloseBubble();
+    } else {
+      root_window_controller->GetStatusAreaWidget()
+          ->notification_tray()
+          ->ShowMessageCenter(false /* show_by_click */);
+    }
+  }
+}
+
 }  // namespace ash

ash/message_center/arc_notification_manager_delegate_impl.h

@@ -21,6 +21,7 @@ class ArcNotificationManagerDelegateImpl
   void GetAppIdByPackageName(const std::string& package_name,
                              GetAppIdByPackageNameCallback callback) override;
   void ShowMessageCenter() override;
+  void HideMessageCenter() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ArcNotificationManagerDelegateImpl);

ash/system/message_center/arc/arc_notification_manager.cc

@@ -229,6 +229,10 @@ void ArcNotificationManager::OpenMessageCenter() {
   delegate_->ShowMessageCenter();
 }
 
+void ArcNotificationManager::CloseMessageCenter() {
+  delegate_->HideMessageCenter();
+}
+
 void ArcNotificationManager::OnNotificationRemoved(const std::string& key) {
   auto it = items_.find(key);
   if (it == items_.end()) {

ash/system/message_center/arc/arc_notification_manager.h

@@ -51,6 +51,7 @@ class ArcNotificationManager
   void OnNotificationUpdated(arc::mojom::ArcNotificationDataPtr data) override;
   void OnNotificationRemoved(const std::string& key) override;
   void OpenMessageCenter() override;
+  void CloseMessageCenter() override;
   void OnDoNotDisturbStatusUpdated(
       arc::mojom::ArcDoNotDisturbStatusPtr status) override;
 

ash/system/message_center/arc/arc_notification_manager_delegate.h

@@ -28,6 +28,9 @@ class ArcNotificationManagerDelegate {
 
   // Shows the message center.
   virtual void ShowMessageCenter() = 0;
+
+  // Hides the message center.
+  virtual void HideMessageCenter() = 0;
 };
 
 }  // namespace ash

ash/system/message_center/arc/arc_notification_manager_unittest.cc

@@ -85,6 +85,7 @@ class FakeArcNotificationManagerDelegate
     std::move(callback).Run(std::string());
   }
   void ShowMessageCenter() override {}
+  void HideMessageCenter() override {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FakeArcNotificationManagerDelegate);

components/arc/common/notifications.mojom

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Next MinVersion: 20
+// Next MinVersion: 21
 
 module arc.mojom;
 
@@ -161,7 +161,7 @@ struct ArcDoNotDisturbStatus {
   bool enabled;
 };
 
-// Next Method ID: 8
+// Next Method ID: 9
 interface NotificationsHost {
   // Set the Do-Not-Disturb status on Chrome side from Android side.
   [MinVersion=18]
@@ -184,6 +184,10 @@ interface NotificationsHost {
   [MinVersion=16]
   // Opens the Chrome OS message center.
   OpenMessageCenter@6();
+
+  [MinVersion=20]
+  // Closes the Chrome OS message center.
+  CloseMessageCenter@8();
 };
 
 // Next Method ID: 9