c++ / mojo changes for 'external window mode'

services/ui/public/interfaces/window_tree_host.mojom

 // 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.
 
 module ui.mojom;
 
 import "services/ui/public/interfaces/window_tree.mojom";
 import "ui/gfx/geometry/mojo/geometry.mojom";
 
 // WindowTreeHost encapsulates a unique underlying platform window, with a tree
 // of windows.
 interface WindowTreeHost {

[sky, 2017/02/28 05:02:22]

As mentioned earlier this needs to be renamed. WindowTreeHost is confusing in
the context of aura given there is already an aura::WindowTreeHost class.

[fwang, 2017/02/28 08:23:53]

The comment should also be fixed as the object can now encapsulate several
platform windows corresponding to the tree roots.

I think it would be great if the name can make explicit this holds a set of
platform windows. Maybe PlatformWindowTree?

[tonikitoo, 2017/03/01 05:05:43]

Right. It essentially creates new ws::Display instances, which by definition
inherits mojom::WindowTreeHost, so I although it confuses with
aura::WindowTreeHost, there some logic behind it.

In any case, I am fine with changing it now for the good.


On 2017/02/28 08:23:53, fwang wrote:
WindowTreeHost reflects an outer platform window, on the server side, and
triggers the creation of an Aura/Mus window on the client side.
Maybe ::CreateRootWindow or ::CreatePlarformWindow ?

   // Sets the size of the platform window.
   SetSize(gfx.mojom.Size size);
 
   // Sets a title string to be displayed on the platform window.
   SetTitle(string title);
 };
 
+// WindowTreeHostFactoryRegistrar is the entry point to obtain a
+// WindowTreeHostFactory instance.
+// It also returns the mojo handle to the unique ws::WindowTree instance,
+// on the server-side.
+//
+// NOTE: WindowTreeHostFactoryRegistrar::Register and
+// WindowTreeHostFactory::CreateWindowTreeHost are put on separate interfaces,
+// so that the interface containing ::CreateWindowTreeHost is obtained by
+// calling ::Register. That eliminates the possibility of ::CreateWindowTreeHost
+// being called before ::Register.
+//
+interface WindowTreeHostFactoryRegistrar {
+   Register(WindowTreeHostFactory& window_tree_host_factory,
+            WindowTree& tree_request,
+            WindowTreeClient client);
+};
+
+// WindowTreeHostFactory triggers the creation of WindowTreeHost instances.
+// One WindowTree/WindowTreeClient pair can serve one or more WindowTreeHost
+// instances.
 interface WindowTreeHostFactory {
-  // Creates a new WindowTreeHost. |tree_client| is queried for the
-  // WindowManager.
-  CreateWindowTreeHost(WindowTreeHost& window_tree_host,
-                       WindowTreeClient tree_client);
+  // Creates a new WindowTreeHost.
+  CreateWindowTreeHost(WindowTreeHost& window_tree_host);
 };