Implement ui::ClipboardMus.

ui/views/mus/window_manager_connection.h

Index: ui/views/mus/window_manager_connection.h
diff --git a/ui/views/mus/window_manager_connection.h b/ui/views/mus/window_manager_connection.h
index 049e09509afb35c23ca2f7a6217e4d5e65610778..2115faa1d687c1bb50fce788c1f8703f5e5ac293 100644
--- a/ui/views/mus/window_manager_connection.h
+++ b/ui/views/mus/window_manager_connection.h
@@ -22,6 +22,7 @@ class Connector;
 }
 
 namespace views {
+class ClipboardMus;
 class NativeWidget;
 class PointerWatcher;
 class ScreenMus;
@@ -31,6 +32,7 @@ class NativeWidgetDelegate;
 
 // Provides configuration to mus in views. This consists of the following:
 // . Provides a Screen implementation backed by mus.
+// . Provides a Clipboard implementation backed by mus.
 // . Creates and owns a WindowTreeConnection.
 // . Registers itself as the factory for creating NativeWidgets so that a
 //   NativeWidgetMus is created.
@@ -88,6 +90,9 @@ class VIEWS_MUS_EXPORT WindowManagerConnection
   // Must be empty on destruction.
   base::ObserverList<PointerWatcher, true> pointer_watchers_;
 
+  // Object owned by Clipboard; explicit deletion method called in destructor.
+  views::ClipboardMus* clipboard_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowManagerConnection);
 };