cros: Adds ShellPort functions for simplified display mode

ash/host/ash_window_tree_host.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 ASH_HOST_ASH_WINDOW_TREE_HOST_H_
 #define ASH_HOST_ASH_WINDOW_TREE_HOST_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 13 matching lines @@
 namespace ash {
 struct AshWindowTreeHostInitParams;
 class InputMethodEventHandler;
 class RootWindowTransformer;
 
 class ASH_EXPORT AshWindowTreeHost {
  public:
   AshWindowTreeHost();
   virtual ~AshWindowTreeHost() {}
 
-  // Creates a new AshWindowTreeHost. The caller owns the returned value.
+  // Creates the appropriate AshWindowTreeHost implementation. The return
+  // value is owned by the RootWindowController associated with the
+  // AshWindowTreeHost.
   static AshWindowTreeHost* Create(

[James Cook, 2017/04/18 00:43:39]

It would be nice if this returned unique_ptr<>, even if the caller immediately
release()'d it.

[sky, 2017/04/18 02:55:10]

I actually had that in an earlier patch, but convinced myself ownership should
happen via the RootWindowController. But that doesn't matter here, so back to
making this return a unique_ptr.

       const AshWindowTreeHostInitParams& init_params);
 
   void set_input_method_handler(InputMethodEventHandler* input_method_handler) {
     input_method_handler_ = input_method_handler;
   }
 
   InputMethodEventHandler* input_method_handler() {
     return input_method_handler_;
   }
 
@@ skipping 24 matching lines @@
   // Translates the native mouse location into screen coordinates.
   void TranslateLocatedEvent(ui::LocatedEvent* event);
 
  private:
   InputMethodEventHandler* input_method_handler_;
 };
 
 }  // namespace ash
 
 #endif  // ASH_HOST_ASH_WINDOW_TREE_HOST_H_