[PresentationAPI] Added/changed public/platform interfaces for start/joinSession

public/platform/modules/presentation/WebPresentationSessionCreateCallback.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 WebPresentationSessionCreateCallback_h
+#define WebPresentationSessionCreateCallback_h
+
+namespace blink {
+
+class WebPresentationSessionClient;
+class WebString;
+
+// A callback passed to the embedder when the frame calls start/joinSession().
+// When creating the session succeeds, returns the implementation of the

[mark a. foltz, 2015/02/18 17:55:29]

..., onSuccess() is invoked with the implementation...

[whywhat, 2015/02/19 14:23:24]

Interface removed, but I'll apply this to the implementation of the WebCallbacks
interface.

+// WebPresentationSession interface. When creating the session fails, returns
+// an appropriate error code.

[mark a. foltz, 2015/02/18 17:55:29]

..., onError() is invoked with an appropriate error message.

[whywhat, 2015/02/19 14:23:24]

Interface removed, but I'll apply this to the implementation of the WebCallbacks
interface.

+class WebPresentationSessionCreateCallback {

[mlamouri (slow - plz ping), 2015/02/18 21:29:16]

Could you inherit from WebCallbacks?
Also, that "WebPresentationSessionCreateCallback" name is odd. What about
"WebPresentationSessionClientCallbacks"?

[whywhat, 2015/02/19 14:23:24]

If I use WebCallbacks, I don't really need a separate interface, do I? I'll
directly inherit from WebCallbacks<WebPresentationSessionClient,
WebPresentationError> in PresentationSessionClientCallbacks in Blink.

+public:
+    virtual ~WebPresentationSessionCreateCallback() { }
+
+    virtual void onSuccess(WebPresentationSessionClient*) = 0;
+    virtual void onError(const WebString& message) = 0;

[mlamouri (slow - plz ping), 2015/02/18 21:08:55]

Instead of passing a simple string, could you pass a struct that contains an
enum (ErrorType) and a string (the message). The Web API will have to expose
DOMException and the DOMException type is actually more important that the
message.

You can take example on WebPushError.

[whywhat, 2015/02/19 14:23:24]

Added WebPresentationError.

+};
+
+} // namespace blink
+
+#endif // WebPresentationSessionCreateCallback_h