Delete MessageViews cleared by "Clear All" after animation.

ui/message_center/views/message_list_view_unittest.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 <map>
 #include <memory>
 #include <utility>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 41 matching lines @@
 
  private:
   Test* test_;
 
   DISALLOW_COPY_AND_ASSIGN(MockNotificationView);
 };
 
 MockNotificationView::MockNotificationView(MessageCenterController* controller,
                                            const Notification& notification,
                                            Test* test)
-    : NotificationView(controller, notification), test_(test) {}
+    : NotificationView(controller, notification), test_(test) {
+  // Calling SetPaintToLayer() to ensure that this view has its own layer.
+  // This layer is needed to enable adding/removal animations.
+  SetPaintToLayer();
+}
 
 MockNotificationView::~MockNotificationView() {}
 
 gfx::Size MockNotificationView::GetPreferredSize() const {
   test_->RegisterCall(GET_PREFERRED_SIZE);
   DCHECK(child_count() > 0);
   return NotificationView::GetPreferredSize();
 }
 
 int MockNotificationView::GetHeightForWidth(int width) const {
@@ skipping 361 matching lines @@
   EXPECT_EQ(2, message_list_view()->child_count());
   EXPECT_TRUE(notification_view2->visible());
 
   RunPendingAnimations();
 
   message_list_view()->ClearAllClosableNotifications(
       message_list_view()->bounds());
 
   RunPendingAnimations();
 
-  // TODO(yhanada): notification_view1 and notification_view2 should be deleted
-  //                here. Uncomment the below test.
-  EXPECT_TRUE(gfx::IntersectRects(notification_view1->bounds(),
-                                  message_list_view()->bounds())
-                  .IsEmpty());
-  EXPECT_TRUE(gfx::IntersectRects(notification_view2->bounds(),
-                                  message_list_view()->bounds())
-                  .IsEmpty());
-  // EXPECT_EQ(0, message_list_view()->child_count());
+  EXPECT_EQ(0, message_list_view()->child_count());
 }
 
 }  // namespace