New AppListView Scroll Behavior.

ui/app_list/views/start_page_view.cc

 // Copyright 2014 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/app_list/views/start_page_view.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/i18n/rtl.h"
@@ skipping 392 matching lines @@
   }
 
   MaybeOpenCustomLauncherPage();
   return true;
 }
 
 bool StartPageView::OnMouseWheel(const ui::MouseWheelEvent& event) {
   // Negative y_offset is a downward scroll.
   if (event.y_offset() < 0) {
     MaybeOpenCustomLauncherPage();
-    return true;
+    return IsCustomLauncherPageActive();
   }
 
   return false;
 }
 
 void StartPageView::OnGestureEvent(ui::GestureEvent* event) {
   if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN &&
       event->details().scroll_y_hint() < 0) {
     MaybeOpenCustomLauncherPage();
   }
@@ skipping 13 matching lines @@
   // is enabled).
   if (event->type() == ui::ET_SCROLL && event->y_offset() < 0)
     MaybeOpenCustomLauncherPage();
 }
 
 TileItemView* StartPageView::GetTileItemView(size_t index) {
   return suggestions_container_->GetTileItemView(index);
 }
 
 }  // namespace app_list