Make apps grid view scroll vertically in experimental app list.

ash/wm/app_list_controller.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 "ash/wm/app_list_controller.h"
 
 #include "ash/ash_switches.h"
 #include "ash/root_window_controller.h"
 #include "ash/screen_util.h"
 #include "ash/shelf/shelf.h"
@@ skipping 491 matching lines @@
     if (!should_snap_back_ && !widget_animator->is_animating())
       view_bounds_ = widget->GetWindowBoundsInScreen();
 
     const int current_page = pagination_model->selected_page();
     const int dir = transition.target_page > current_page ? -1 : 1;
 
     const double progress = 1.0 - pow(1.0 - transition.progress, 4);
     const int shift = kMaxOverScrollShift * progress * dir;
 
     gfx::Rect shifted(view_bounds_);
-    shifted.set_x(shifted.x() + shift);
+    // Experimental app list scrolls vertically, so make the overscroll
+    // vertical.
+    if (app_list::switches::IsExperimentalAppListEnabled())
+      shifted.set_y(shifted.y() + shift);
+    else
+      shifted.set_x(shifted.x() + shift);
     widget->SetBounds(shifted);
     should_snap_back_ = true;
   } else if (should_snap_back_) {
     should_snap_back_ = false;
     ui::ScopedLayerAnimationSettings animation(widget_animator);
     animation.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
         app_list::kOverscrollPageTransitionDurationMs));
     widget->SetBounds(view_bounds_);
   }
 }
 
 }  // namespace ash