Windows docking should get triggered by pressing against the screen edge

ash/wm/workspace/snap_sizer.h

Index: ash/wm/workspace/snap_sizer.h
diff --git a/ash/wm/workspace/snap_sizer.h b/ash/wm/workspace/snap_sizer.h
index bd5f719ae482d1d78be1c20d70fd0895e3eb0703..baf94cd7818290b734e3dd14b28ea5af895933c7 100644
--- a/ash/wm/workspace/snap_sizer.h
+++ b/ash/wm/workspace/snap_sizer.h
@@ -63,6 +63,9 @@ class ASH_EXPORT SnapSizer {
   // For unit test purposes this function is not private.
   gfx::Rect GetTargetBoundsForSize(size_t size_index) const;
 
+  // Returns true when snapping sequence is at its last (docking) step.
+  bool end_of_sequence() const { return end_of_sequence_; }
+
  private:
   // Calculates the amount to increment by. This returns one of -1, 0 or 1 and
   // is intended to by applied to |size_index_|. |x| is the current
@@ -96,6 +99,10 @@ class ASH_EXPORT SnapSizer {
   // bounds should get.
   int size_index_;
 
+  // Set to true when an attempt is made to increment |size_index_| past
+  // the size of |usable_width_|.
+  bool end_of_sequence_;
+
   // If set, |size_index_| will get ignored and the single button default
   // setting will be used instead.
   bool resize_disabled_;