Sends the scroll gesture to scrollbar.

ui/message_center/message_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/message_center/message_view.h"
 
 #include "grit/ui_resources.h"
 #include "grit/ui_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/models/simple_menu_model.h"
@@ skipping 246 matching lines @@
     return;
   }
 
   if (event->type() == ui::ET_GESTURE_LONG_PRESS) {
     ShowMenu(event->location());
     event->SetHandled();
     return;
   }
 
   SlideOutView::OnGestureEvent(event);
-  if (event->handled())
-    return;
+  // Do not return here by checking handled(). SlideOutView calls SetHandled()
+  // even though the scroll gesture doesn't make no (or little) effects on the
+  // slide-out behavior. See http://crbug.com/172991
 
   if (!event->IsScrollGestureEvent())
     return;
 
   if (scroller_)
     scroller_->OnGestureEvent(event);
   event->SetHandled();
 }
 
 void MessageView::ButtonPressed(views::Button* sender,
@@ skipping 17 matching lines @@
       gfx::Rect(screen_location, gfx::Size()),
       views::MenuItemView::TOPRIGHT,
       views::MenuRunner::HAS_MNEMONICS));
 }
 
 void MessageView::OnSlideOut() {
   list_delegate_->SendRemoveNotification(notification_.id);
 }
 
 }  // namespace message_center