Wires up drags to pointer watcher adapter.

ash/aura/pointer_watcher_adapter.h

Index: ash/aura/pointer_watcher_adapter.h
diff --git a/ash/aura/pointer_watcher_adapter.h b/ash/aura/pointer_watcher_adapter.h
index b17f8cbd00b610c64f163353020738adf695e262..fa51738714a5ad447e553d88658977ed60a951fa 100644
--- a/ash/aura/pointer_watcher_adapter.h
+++ b/ash/aura/pointer_watcher_adapter.h
@@ -34,7 +34,9 @@ class ASH_EXPORT PointerWatcherAdapter : public ui::EventHandler {
   ~PointerWatcherAdapter() override;
 
   // See WmShell::AddPointerWatcher() for details.
-  void AddPointerWatcher(views::PointerWatcher* watcher, bool wants_moves);
+  void AddPointerWatcher(views::PointerWatcher* watcher,
+                         bool wants_moves,

[sky, 2016/08/24 23:32:30]

Code with lots of boolean parameters gets hard to read and folks end up
introducing temporaries to improve readability. Go with a bitmask to make it
easier to follow.

[sammiequon, 2016/08/25 23:11:18]

Done. Though not sure where is the best place to put such an enum.

+                         bool wants_drags);
   void RemovePointerWatcher(views::PointerWatcher* watcher);
 
   // ui::EventHandler:
@@ -58,6 +60,7 @@ class ASH_EXPORT PointerWatcherAdapter : public ui::EventHandler {
   // observers wanting moves too.
   base::ObserverList<views::PointerWatcher, true> non_move_watchers_;
   base::ObserverList<views::PointerWatcher, true> move_watchers_;
+  base::ObserverList<views::PointerWatcher, true> drag_watchers_;
 
   DISALLOW_COPY_AND_ASSIGN(PointerWatcherAdapter);
 };