Add a Display and ContextProvider concept to mojom, use to recreate

mojo/services/surfaces/public/interfaces/display.mojom

+// 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.
+
+module mojo;
+
+import "gpu/public/interfaces/command_buffer.mojom";
+import "gpu/public/interfaces/gpu.mojom";
+import "gpu/public/interfaces/viewport_parameter_listener.mojom";
+import "surfaces/public/interfaces/surfaces.mojom";
+
+interface Display {
+  // Submits a new frame to the display to be drawn when possible. The callback
+  // will be run after the frame has been issued to the display but possibly
+  // before the frame is actually visible.
+  //
+  // The Display will be resized to the size of |frame|'s root pass.

[qsr, 2015/02/20 11:25:47]

Does pass has a specific meaning in this context? I'm feeling that it might not
be the right word here.

[jamesr, 2015/02/20 22:01:05]

mojo.Pass is a mojom type and |frame| has a field called |passes|. Expanded on
this comment a bit

+  //
+  // Any resources submitted in the frame will be returned via the
+  // ResourceReturner associated with the Display at construction time.
+  SubmitFrame(Frame frame) => ();
+};
+
+// DisplayFactory creates new Display instances.
+interface DisplayFactory {
+  // Create associates a Display that will draw to contexts associated with
+  // |context_provider|. The display will try to stay in sync with the
+  // vsync parameters from |viewport_parameter_listener|, if supplied. Any
+  // resources submitted to the display will be returned via the |returner|, if
+  // supplied.
+  Create(ContextProvider context_provider,
+         ViewportParameterListener? viewport_parameter_listener,
+         ResourceReturner? returner,
+         Display& display_request);
+};
+