Mus Demo: Demonstrate external window mode

services/ui/demo/window_tree_data.h

 // Copyright 2017 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 SERVICES_UI_DEMO_WINDOW_TREE_DATA_H_
 #define SERVICES_UI_DEMO_WINDOW_TREE_DATA_H_
 
 #include "base/memory/ptr_util.h"
 #include "base/timer/timer.h"
+#include "services/ui/public/interfaces/window_tree_host.mojom.h"
 
 namespace aura {
 class Window;
 class WindowTreeHostMus;
 }  // namespace aura
 
 namespace aura_extra {
 class ImageWindowDelegate;
 }  // namespace aura_extra
 
 namespace ui {
 namespace demo {
 
 class WindowTreeData {
  public:
   explicit WindowTreeData(int square_size);

[kylechar, 2017/02/21 15:15:11]

What is the difference between the two constructors? Can you add comments.

[fwang, 2017/02/21 17:30:19]

The new one is only used in external mode. I've moved it to
WindowTreeDataExternal so that it is clearer.

+  explicit WindowTreeData(mojom::WindowTreeHostFactory* factory,

[kylechar, 2017/02/21 15:15:11]

Only constructor with a single parameter should be explicit.

[fwang, 2017/02/21 17:30:19]

Done.

+                          mojom::WindowTreeClientPtr tree_client,
+                          int square_size);
   ~WindowTreeData();
 
   // Initializes the window tree host and start drawing frames.
   void Init(std::unique_ptr<aura::WindowTreeHostMus> window_tree_host);
   bool IsInitialized() const { return !!window_tree_host_; }
 
  private:
   // Draws one frame, incrementing the rotation angle.
   void DrawFrame();
 
   // Helper function to retrieve the window to which we draw the bitmap.
   aura::Window* bitmap_window();
 
   // The Window tree host corresponding to this data.
   std::unique_ptr<aura::WindowTreeHostMus> window_tree_host_;
 
+  // When the WindowTreeData is created with WindowTreeHostFactory, this holds
+  // the Mojo pointer to the window tree host.
+  mojom::WindowTreeHostPtr host_;

[kylechar, 2017/02/21 15:15:11]

Is this only needed for external mode? Can we somehow have only shared code in
WindowTreeData?

[fwang, 2017/02/21 17:30:19]

Yes. All these data will be moved to a WindowTreeDataExternal.

+
   // Destroys itself when the window gets destroyed.
   aura_extra::ImageWindowDelegate* window_delegate_ = nullptr;
 
   // Timer for calling DrawFrame().
   base::RepeatingTimer timer_;
 
   // Current rotation angle for drawing.
   double angle_ = 0.0;
 
   // Size in pixels of the square to draw.
   const int square_size_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeData);
 };
 
 }  // namespace demo
 }  // namespace ui
 
 #endif  // SERVICES_UI_DEMO_WINDOW_TREE_DATA_H_