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

ash/accelerators/accelerator_controller.cc

Index: ash/accelerators/accelerator_controller.cc
diff --git a/ash/accelerators/accelerator_controller.cc b/ash/accelerators/accelerator_controller.cc
index d80cfea83c1a2deec1c5d574b61f31fa543acb62..57eb05c70be5bd54ff868f884c3e5d10798bd8da 100644
--- a/ash/accelerators/accelerator_controller.cc
+++ b/ash/accelerators/accelerator_controller.cc
@@ -836,9 +836,11 @@ bool AcceleratorController::PerformAction(int action,
         break;
       }
 
-      internal::SnapSizer::SnapWindow(window,
-          action == WINDOW_SNAP_LEFT ? internal::SnapSizer::LEFT_EDGE :
-                                       internal::SnapSizer::RIGHT_EDGE);
+      using internal::SnapSizer;

[varkha, 2013/08/30 17:13:25]

Is there a reason that
ScopedLayerAnimationSettings::SetPreemptionStrategy(ui::LayerAnimator::REPLACE_QUEUED_ANIMATIONS);
is not used here? Would it belong inside the SnapWindow()?

[pkotwicz, 2013/08/30 21:10:57]

Good catch!
You are right that we probably should be animating snapping left and right. We
do not animate when snapping left and right as a result of FrameMaximizeButton
and we probably should.
I need to figure out whether we want to animate as a result of side maximizing
via WorkspaceWindowResizer
In terms of AcceleratorController, we do not animate for WINDOW_POSITION_CENTER
(via Alt+Shift+"=") So for better or for worse we are consistent there.

(For the sake of fun, there is a completely unrelated partial maximize mode that
you can enter by double clicking the borders of a window which is also not
animated)

+      SnapSizer::Edge edge = (action == WINDOW_SNAP_LEFT) ?
+          SnapSizer::LEFT_EDGE : SnapSizer::RIGHT_EDGE;
+      if (SnapSizer::CanSnapWindow(window, edge))
+        SnapSizer::SnapWindow(window, edge, SnapSizer::STEP_YES);
       return true;
     }
     case WINDOW_MINIMIZE: {