Plumbing from WebPresentationClient to the Presentation Mojo service for

content/renderer/presentation/presentation_dispatcher.h

+// 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.
+
+#ifndef CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_
+#define CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_
+
+#include "content/common/presentation/presentation_service.mojom.h"
+#include "content/public/renderer/render_frame_observer.h"
+#include "third_party/WebKit/public/platform/WebPresentationClient.h"
+
+namespace content {
+
+// PresentationDispatcher is a delegate for Presentation API messages used by
+// Blink. It forwards the calls to the Mojo PresentationService.
+class PresentationDispatcher
+    : public RenderFrameObserver,
+      public blink::WebPresentationClient {
+ public:
+  explicit PresentationDispatcher(RenderFrame* render_frame);
+  ~PresentationDispatcher() override;
+
+ private:
+  // WebPresentationClient implementation.
+  virtual void setController(
+      blink::WebPresentationController* controller);

[mark a. foltz, 2015/01/27 21:56:09]

override?

[whywhat, 2015/01/28 01:52:38]

As suggested by another reviewer, implementations of Blink interfaces don't use
override in case the interface has to be changed (so that the change to the
interface doesn't prevent Blink from rolling into Chromium).

+  virtual void updateAvailableChangeWatched(bool watched);

[mark a. foltz, 2015/01/27 21:56:09]

override?

[whywhat, 2015/01/28 01:52:38]

Ditto.

+
+  void OnScreenAvailabilityChanged(bool available);
+
+  void ConnectToPresentationServiceIfNeeded();
+
+  // Used as a weak reference. Can be null since lifetime is bound to the frame.

[mark a. foltz, 2015/01/27 21:56:09]

Should this be refcounted?  Or is it simply set or |null| and the lifetime is
controlled entirely by one other object?

[whywhat, 2015/01/28 01:52:38]

Yes, controller lives on the Blink heap (Oilpan) so can't be ref counted from
here AFAIK. The dispatcher is updated with the correct pointer when needed.

+  blink::WebPresentationController* controller_;

[mark a. foltz, 2015/01/27 21:56:09]

Does this need fwd declaration?

[whywhat, 2015/01/28 01:52:38]

Not really since WebPresentationClient already forward declares it to be able to
define its setController() method.

+  presentation::PresentationServicePtr presentation_service_;

[mark a. foltz, 2015/01/27 21:56:09]

Ditto

[whywhat, 2015/01/28 01:52:38]

This is defined in the presentation_service.mojom.h included in this file.

+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_