Restructure public side of view_manager service.

mojo/services/public/cpp/view_manager/view_manager.h

-// Copyright 2014 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 MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_MANAGER_H_
-#define MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_MANAGER_H_
-
-#include <string>
-#include <vector>
-
-#include "mojo/services/public/cpp/view_manager/types.h"
-
-namespace mojo {
-class View;
-
-// Encapsulates a connection to the view manager service.
-// A unique connection is made for every unique embed path for an app. e.g. for
-// app B embed by the following paths: A->B, A->C->B - there are two connections
-// and thus two instances of this class.
-class ViewManager {
- public:
-  // Returns the URL of the application that embedded this application.
-  virtual const std::string& GetEmbedderURL() const = 0;
-
-  // Returns all root views known to this connection.
-  virtual const std::vector<View*>& GetRoots() const = 0;
-
-  // Returns a View known to this connection.
-  virtual View* GetViewById(Id id) = 0;
-
- protected:
-  virtual ~ViewManager() {}
-};
-
-}  // namespace mojo
-
-#endif  // MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_MANAGER_H_