Changes how window manager obtains WindowTree from mus

components/mus/public/interfaces/window_manager.mojom

Index: components/mus/public/interfaces/window_manager.mojom
diff --git a/components/mus/public/interfaces/window_manager.mojom b/components/mus/public/interfaces/window_manager.mojom
index 571ca354d316ef500440d07c5c280b7472672991..ed0ffe172a1023bdfbbf6e7dd0af7c276247af1f 100644
--- a/components/mus/public/interfaces/window_manager.mojom
+++ b/components/mus/public/interfaces/window_manager.mojom
@@ -7,6 +7,7 @@ module mus.mojom;
 import "components/mus/public/interfaces/cursor.mojom";
 import "components/mus/public/interfaces/event_matcher.mojom";
 import "components/mus/public/interfaces/window_manager_constants.mojom";
+import "components/mus/public/interfaces/window_tree_constants.mojom";
 import "ui/events/mojo/event.mojom";
 import "ui/gfx/geometry/mojo/geometry.mojom";
 
@@ -54,6 +55,13 @@ interface WindowManager {
   // and the client area should be equivalent to the window area. Type: bool
   const string kRemoveStandardFrame_Property = "prop:remove-standard-frame";
 
+  // Called immediately when the WindowManager is obtained.
+  OnConnect(uint16 client_id);
+
+  // Called when a new display is added. |root| gives the root window specific
+  // to this WindowManager for |display|.
+  WmNewDisplayAdded(Display display, WindowData root, bool parent_drawn);
+
   // When the WindowManager completes a request it must call back to
   // WindowManagerClient::WmResponse().
   WmSetBounds(uint32 change_id, uint32 window_id, gfx.mojom.Rect bounds);