Changes how window manager obtains WindowTree from mus

components/mus/public/cpp/window_tree_client_delegate.h

Index: components/mus/public/cpp/window_tree_client_delegate.h
diff --git a/components/mus/public/cpp/window_tree_client_delegate.h b/components/mus/public/cpp/window_tree_client_delegate.h
index 877bd60c209f74978e90af5acc0794a2b9f739bf..41f09dfdbf02cdf422b2115fa100220311225f01 100644
--- a/components/mus/public/cpp/window_tree_client_delegate.h
+++ b/components/mus/public/cpp/window_tree_client_delegate.h
@@ -19,19 +19,7 @@ namespace mus {
 class Window;
 class WindowTreeClient;
 
-// Interface implemented by an application using the window manager.
-//
-// WindowTreeClient is deleted by any of the following:
-// . If all the roots of the connection are destroyed and the connection is
-//   configured to delete when there are no roots (the default). This happens
-//   if the owner of the roots Embed()s another app in all the roots, or all
-//   the roots are explicitly deleted.
-// . The connection to the window manager is lost.
-// . Explicitly by way of calling delete.
-//
-// When the WindowTreeClient is deleted all windows are deleted (and observers
-// notified). This is followed by notifying the delegate by way of
-// OnClientDestroyed().
+// Interface implemented by an application using mus.
 class WindowTreeClientDelegate {
  public:
   // Called when the application implementing this interface is embedded at