First cut at supporting activation in the window manager

mojo/services/view_manager/server_view_delegate.h

Index: mojo/services/view_manager/server_view_delegate.h
diff --git a/mojo/services/view_manager/server_view_delegate.h b/mojo/services/view_manager/server_view_delegate.h
index 5798a6509a6293760133907d3c695b118b5f3c78..24e5f8f8e71731651e40deb48e48e4bbf82ba662 100644
--- a/mojo/services/view_manager/server_view_delegate.h
+++ b/mojo/services/view_manager/server_view_delegate.h
@@ -36,6 +36,10 @@ class MOJO_VIEW_MANAGER_EXPORT ServerViewDelegate {
 
   virtual void OnViewSurfaceIdChanged(const ServerView* view) = 0;
 
+  virtual void OnViewReordered(const ServerView* view,
+                               const ServerView* relative,
+                               OrderDirection direction) = 0;
+
   virtual void OnWillChangeViewVisibility(const ServerView* view) = 0;
 
  protected: