Revert 124385 - Allows tab dragging when maximized on aura. To fix it I made it so

ash/wm/workspace/workspace_window_resizer.h

Index: ash/wm/workspace/workspace_window_resizer.h
===================================================================
--- ash/wm/workspace/workspace_window_resizer.h	(revision 124386)
+++ ash/wm/workspace/workspace_window_resizer.h	(working copy)
@@ -43,9 +43,6 @@
   // Returns true if the window touches the bottom of the work area.
   bool WindowTouchesBottomOfScreen() const;
 
-  // True if the window size (height) should be constrained.
-  const bool constrain_size_;
-
   DISALLOW_COPY_AND_ASSIGN(WorkspaceWindowResizer);
 };