Supporting shrinking/enlarging for notifications

ui/message_center/views/toast_contents_view.h

Index: ui/message_center/views/toast_contents_view.h
diff --git a/ui/message_center/views/toast_contents_view.h b/ui/message_center/views/toast_contents_view.h
index bd488bea20050adc12f959bbce514e19d42dae50..d69a360e1d939d4de2bc657325a386a934140e28 100644
--- a/ui/message_center/views/toast_contents_view.h
+++ b/ui/message_center/views/toast_contents_view.h
@@ -27,6 +27,10 @@ class View;
 
 namespace message_center {
 
+namespace test {
+class MessagePopupCollectionTest;
+}
+
 class MessagePopupCollection;
 class MessageView;
 class Notification;
@@ -69,7 +73,7 @@ class ToastContentsView : public views::WidgetDelegateView,
   gfx::Point origin() { return origin_; }
   gfx::Rect bounds() { return gfx::Rect(origin_, preferred_size_); }
 
-  const std::string& id() { return id_; }
+  const std::string& id() const { return id_; }
 
   // Overridden from views::View:
   void OnMouseEntered(const ui::MouseEvent& event) override;
@@ -79,6 +83,8 @@ class ToastContentsView : public views::WidgetDelegateView,
   void GetAccessibleState(ui::AXViewState* state) override;
 
  private:
+  friend class test::MessagePopupCollectionTest;
+
   // Overridden from MessageCenterController:
   void ClickOnNotification(const std::string& notification_id) override;
   void RemoveNotification(const std::string& notification_id,
@@ -102,6 +108,9 @@ class ToastContentsView : public views::WidgetDelegateView,
   void OnDisplayChanged() override;
   void OnWorkAreaChanged() override;
 
+  // Recalculates preferred size from underlying view and notifies about it.
+  void UpdatePreferredSize();
+
   // Initialization and update.
   void CreateWidget(gfx::NativeView parent);