Ensure that mask layer is of the same size as the owning layer.

ui/views/bubble/tray_bubble_view.cc

 // Copyright (c) 2012 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/bubble/tray_bubble_view.h"
 
 #include <algorithm>
 
 #include "base/macros.h"
 #include "cc/paint/paint_flags.h"
@@ skipping 247 matching lines @@
 }
 
 gfx::Insets TrayBubbleView::GetBorderInsets() const {
   return bubble_border_->GetInsets();
 }
 
 int TrayBubbleView::GetDialogButtons() const {
   return ui::DIALOG_BUTTON_NONE;
 }
 
+void TrayBubbleView::SizeToContents() {
+  BubbleDialogDelegateView::SizeToContents();
+  bubble_content_mask_->layer()->SetBounds(layer()->bounds());
+}
+
 void TrayBubbleView::OnBeforeBubbleWidgetInit(Widget::InitParams* params,
                                               Widget* bubble_widget) const {
   // Apply a WM-provided shadow (see ui/wm/core/).
   params->shadow_type = Widget::InitParams::SHADOW_TYPE_DROP;
   params->shadow_elevation = wm::ShadowElevation::LARGE;
 }
 
 void TrayBubbleView::OnWidgetClosing(Widget* widget) {
   BubbleDialogDelegateView::OnWidgetClosing(widget);
   --g_current_tray_bubble_showing_count_;
@@ skipping 99 matching lines @@
 
 void TrayBubbleView::ViewHierarchyChanged(
     const ViewHierarchyChangedDetails& details) {
   if (details.is_add && details.child == this) {
     details.parent->SetPaintToLayer();
     details.parent->layer()->SetMasksToBounds(true);
   }
 }
 
 }  // namespace views