Fix glitch when creating notification during drag

In UnifiedSystemTray, we only optimize expand/collapse transform when
there is no notification. We should update the layer transform state
when a notification is created during dragging system tray.

TEST=manual
BUG=863577

Change-Id: Iaff5438a9e8f50b621a48cff5c9f197f48d7617e
Reviewed-on: https://chromium-review.googlesource.com/1168709Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581826}

ash/system/unified/unified_message_center_view.cc

@@ -17,6 +17,7 @@
 #include "ui/message_center/views/notification_control_buttons_view.h"
 #include "ui/views/controls/scroll_view.h"
 #include "ui/views/layout/box_layout.h"
+#include "ui/views/widget/widget.h"
 
 using message_center::MessageCenter;
 using message_center::MessageView;
@@ -232,6 +233,8 @@ void UnifiedMessageCenterView::NotifyHeightBelowScroll() {
 
 void UnifiedMessageCenterView::Update() {
   SetVisible(message_list_view_->GetNotificationCount() > 0);
+  if (GetWidget() && !GetWidget()->IsClosed())
+    tray_controller_->OnMessageCenterVisibilityUpdated();
 
   size_t notification_count = message_list_view_->GetNotificationCount();
   // TODO(tetsui): This is O(n^2).

ash/system/unified/unified_system_tray_controller.cc

@@ -171,6 +171,11 @@ void UnifiedSystemTrayController::OnClearAllAnimationEnded() {
       message_center::MessageCenter::RemoveType::NON_PINNED);
 }
 
+void UnifiedSystemTrayController::OnMessageCenterVisibilityUpdated() {
+  if (bubble_)
+    bubble_->UpdateTransform();
+}
+
 void UnifiedSystemTrayController::BeginDrag(const gfx::Point& location) {
   drag_init_point_ = location;
   was_expanded_ = IsExpanded();

ash/system/unified/unified_system_tray_controller.h

@@ -62,6 +62,9 @@ class ASH_EXPORT UnifiedSystemTrayController : public gfx::AnimationDelegate {
   // Called when notification removing animation is finished. Called from the
   // view.
   void OnClearAllAnimationEnded();
+  // Called when message center visibility is changed. Called from the
+  // view.
+  void OnMessageCenterVisibilityUpdated();
 
   // Handle finger dragging and expand/collapse the view. Called from view.
   void BeginDrag(const gfx::Point& location);