Wires up drags to pointer watcher adapter.

ash/common/wm_shell.h

Index: ash/common/wm_shell.h
diff --git a/ash/common/wm_shell.h b/ash/common/wm_shell.h
index 2c05b0cf0c297498d9c985ed57cb241629e7f4a6..3fa696596e21ca2cad74be076db77f71a19cb43e 100644
--- a/ash/common/wm_shell.h
+++ b/ash/common/wm_shell.h
@@ -322,10 +322,13 @@ class ASH_EXPORT WmShell {
   void RemoveShellObserver(ShellObserver* observer);
 
   // If |wants_moves| is true PointerWatcher::OnPointerEventObserved() is
-  // called for pointer move events. Enabling pointer moves may incur a
-  // performance hit and should be avoided if possible.
+  // called for pointer move events. If |wants_drags| is true
+  // PointerWatcher::OnPointerEventObserved() is called for pointer drag events.
+  // Enabling pointer moves or drags may incur a performance hit and should be
+  // avoided if possible.
   virtual void AddPointerWatcher(views::PointerWatcher* watcher,
-                                 bool wants_moves) = 0;
+                                 bool wants_moves,
+                                 bool wants_drags) = 0;
   virtual void RemovePointerWatcher(views::PointerWatcher* watcher) = 0;
 
   // TODO: Move these back to LockStateController when that has been moved.