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

ash/wm/gestures/system_pinch_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/gestures/system_pinch_handler.h"
 
 #include "ash/launcher/launcher.h"
 #include "ash/screen_ash.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
@@ skipping 68 matching lines @@
       break;
     }
 
     case ui::ET_GESTURE_MULTIFINGER_SWIPE: {
       phantom_.Hide();
       pinch_factor_ = 1.0;
       phantom_state_ = PHANTOM_WINDOW_NORMAL;
 
       if (event.details().swipe_left() || event.details().swipe_right()) {
         // Snap for left/right swipes.
-        ui::ScopedLayerAnimationSettings settings(
-            target_->layer()->GetAnimator());
-        internal::SnapSizer::SnapWindow(target_,
-            event.details().swipe_left() ? internal::SnapSizer::LEFT_EDGE :
-                                           internal::SnapSizer::RIGHT_EDGE);
+        using internal::SnapSizer;
+        if (SnapSizer::CanSnapWindow(target_)) {
+          ui::ScopedLayerAnimationSettings settings(
+              target_->layer()->GetAnimator());
+          SnapSizer::Edge edge = event.details().swipe_left() ?
+              SnapSizer::LEFT_EDGE : SnapSizer::RIGHT_EDGE;
+          SnapSizer::SnapWindow(target_, edge, SnapSizer::STEP_NO);
+        }
       } else if (event.details().swipe_up()) {
         if (!wm::IsWindowMaximized(target_) &&
-            !wm::IsWindowFullscreen(target_))
+            !wm::IsWindowFullscreen(target_) &&
+            wm::CanMaximizeWindow(target_))
           wm::MaximizeWindow(target_);
       } else if (event.details().swipe_down()) {
         wm::MinimizeWindow(target_);
       } else {
         NOTREACHED() << "Swipe happened without a direction.";
       }
       break;
     }
 
     default:
@@ skipping 29 matching lines @@
     phantom_state_ = PHANTOM_WINDOW_MINIMIZED;
     return rect;
   }
 
   phantom_state_ = PHANTOM_WINDOW_NORMAL;
   return window->bounds();
 }
 
 }  // namespace internal
 }  // namespace ash