Mandoline UI Process: Update namespaces and file names

components/mus/view_tree_host_delegate.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_MUS_VIEW_TREE_HOST_DELEGATE_H_
 #define COMPONENTS_MUS_VIEW_TREE_HOST_DELEGATE_H_
 
-namespace view_manager {
+namespace mus {
 
 class ViewTreeImpl;
 
 // A ViewTreeHostDelegate interface is implemented by an object that
 // has the ViewTreeImpl that is associated with the ViewTreeHostImpl that holds
 // a pointer to this object. Typically, a ViewTreeHostDelegate will also manage
 // the lifetime of the ViewTreeHostImpl and will delete the object when it gets
 // informed of when the Display of the root is closed.
 class ViewTreeHostDelegate {
  public:
   // Called when the window associated with the root is completely initialized
   // (i.e. the ViewportMetrics for the display is known).
   virtual void OnDisplayInitialized() = 0;
 
   // Called when the window associated with the root is closed.
   virtual void OnDisplayClosed() = 0;
 
   // Returns the ViewTreeImpl associated with the delegate.
   virtual ViewTreeImpl* GetViewTree() = 0;
 
  protected:
   virtual ~ViewTreeHostDelegate() {}
 };
 
-}  // namespace view_manager
+}  // namespace mus
 
 #endif  // COMPONENTS_MUS_VIEW_TREE_HOST_DELEGATE_H_