Gets events dispatching working in mushrome

ui/aura/mus/window_tree_client.h

Index: ui/aura/mus/window_tree_client.h
diff --git a/ui/aura/mus/window_tree_client.h b/ui/aura/mus/window_tree_client.h
index a8b1f1368de07019ac84771ece0cb18361f9df82..f19e19aa565ea36c7472c0bdf6305300689708b1 100644
--- a/ui/aura/mus/window_tree_client.h
+++ b/ui/aura/mus/window_tree_client.h
@@ -113,7 +113,9 @@ class AURA_EXPORT WindowTreeClient
   void ConnectViaWindowTreeFactory();
 
   // Establishes the connection by way of WindowManagerWindowTreeFactory.
-  void ConnectAsWindowManager();
+  // If |dispatch_from_host| is true then event dispatch always happens from the
+  // host. This is only useful if mus has a single client.
+  void ConnectAsWindowManager(bool dispatch_from_host = false);
 
   service_manager::Connector* connector() { return connector_; }
   ui::Gpu* gpu() { return gpu_.get(); }
@@ -608,6 +610,9 @@ class AURA_EXPORT WindowTreeClient
   // Set to true once OnWmDisplayAdded() is called.
   bool got_initial_displays_ = false;
 
+  // See ConnectAsWindowManager() for details.
+  bool dispatch_from_host_ = false;
+
   base::WeakPtrFactory<WindowTreeClient> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeClient);