Only support left/right maximizing at 50% width when the --ash-enable-alternate-caption-button

ash/wm/toplevel_window_event_handler.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/toplevel_window_event_handler.h"
 
 #include "ash/shell.h"
 #include "ash/wm/property_util.h"
 #include "ash/wm/resize_shadow_controller.h"
 #include "ash/wm/window_properties.h"
@@ skipping 283 matching lines @@
         // Minimize/maximize.
         if (event->details().velocity_y() > 0 &&
             wm::CanMinimizeWindow(target)) {
           wm::MinimizeWindow(target);
           SetWindowAlwaysRestoresToRestoreBounds(target, true);
           SetRestoreBoundsInParent(target, pre_drag_window_bounds_);
         } else if (wm::CanMaximizeWindow(target)) {
           SetRestoreBoundsInParent(target, pre_drag_window_bounds_);
           wm::MaximizeWindow(target);
         }
-      } else if (wm::CanSnapWindow(target) &&
+      } else if (internal::SnapSizer::CanSnapWindow(target) &&
                  fabs(event->details().velocity_x()) >
                  kMinHorizVelocityForWindowSwipe) {
         // Snap left/right.
         ui::ScopedLayerAnimationSettings scoped_setter(
             target->layer()->GetAnimator());
         scoped_setter.SetPreemptionStrategy(
             ui::LayerAnimator::REPLACE_QUEUED_ANIMATIONS);
-        internal::SnapSizer::SnapWindow(target,
-            event->details().velocity_x() < 0 ?
-            internal::SnapSizer::LEFT_EDGE : internal::SnapSizer::RIGHT_EDGE);
+        using internal::SnapSizer;
+        SnapSizer::Edge edge = event->details().velocity_x() < 0 ?
+            SnapSizer::LEFT_EDGE : SnapSizer::RIGHT_EDGE;
+        SnapSizer::SnapWindow(target, edge, SnapSizer::STEP_NO);
       }
       break;
     }
     default:
       return;
   }
 
   event->StopPropagation();
 }
 
@@ skipping 200 matching lines @@
 void ToplevelWindowEventHandler::ResizerWindowDestroyed() {
   // We explicitly don't invoke RevertDrag() since that may do things to window.
   // Instead we destroy the resizer.
   window_resizer_.reset();
 
   // End the move loop. This does nothing if we're not in a move loop.
   EndMoveLoop();
 }
 
 }  // namespace ash