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

ash/wm/gestures/system_pinch_handler.cc

Index: ash/wm/gestures/system_pinch_handler.cc
diff --git a/ash/wm/gestures/system_pinch_handler.cc b/ash/wm/gestures/system_pinch_handler.cc
index a0f5d12e00b04642df7a0f6a552d6e5dd80ac397..6a27146cc7fc885cdb0ab94d70c455e38919d25c 100644
--- a/ash/wm/gestures/system_pinch_handler.cc
+++ b/ash/wm/gestures/system_pinch_handler.cc
@@ -11,7 +11,6 @@
 #include "ash/wm/property_util.h"
 #include "ash/wm/window_animations.h"
 #include "ash/wm/window_util.h"
-#include "ash/wm/workspace/snap_sizer.h"
 #include "ui/aura/window.h"
 #include "ui/base/events/event_constants.h"
 #include "ui/base/gestures/gesture_types.h"
@@ -86,15 +85,19 @@ SystemGestureStatus SystemPinchHandler::ProcessGestureEvent(
 
       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);
+        if (wm::CanSnapWindow(target_)) {
+          ui::ScopedLayerAnimationSettings settings(
+              target_->layer()->GetAnimator());
+           wm::SnapWindowToEdge(target_,
+              event.details().swipe_left() ? wm::SNAP_LEFT_EDGE :
+                                             wm::SNAP_RIGHT_EDGE);
+        }
       } 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 {