[Presentation API] 1-UA presentation support + presenter APIs.

content/common/presentation/presentation_service.mojom

Index: content/common/presentation/presentation_service.mojom
diff --git a/content/common/presentation/presentation_service.mojom b/content/common/presentation/presentation_service.mojom
index e201791642a0fc5ccf4128ecf03dff3e1d27e365..891791a60e7aefbef8899fb33df350e518f6c8e4 100644
--- a/content/common/presentation/presentation_service.mojom
+++ b/content/common/presentation/presentation_service.mojom
@@ -104,6 +104,17 @@ interface PresentationService {
   // PresentationServiceClient::OnSessionMessagesReceived.
   // This is called after a presentation session is created.
   ListenForSessionMessages(PresentationSessionInfo sessionInfo);
+
+  // Gets a single receiver PresentationSessionInfo object for the
+  // offscreen presentation hosted on the offscreen tab containing this frame.
+  // If the calling frame is not the main frame of an offscreen tab,
+  // null will be returned.

[mark a. foltz, 2015/10/12 21:56:10]

This might be simpler as,

// Returns a PresentationSessionInfo object for this frame, if it is the
// main frame of an offscreen presentation.  Otherwise returns null.

[imcheng, 2015/10/17 01:00:24]

Done.

+  // Otherwise, a PresentationSessionInfo object will be returned,
+  // with url set to empty, and id set to the ID of the offscreen presentation.

[mark a. foltz, 2015/10/12 21:56:10]

Can we look up the URL from the PresentationRequest that generated the offscreen
presentation?

[imcheng, 2015/10/17 01:00:24]

We can certainly. But I believe spec says URL is undefined for receiver
PresentationConnection objects so there is no use in including it here.

+  // If a receiver presentation session never becomes available, null will be
+  // returned right before this request becomes invalid (e.g., due to frame
+  // deletion, frame navigation).
+  GetPresentationReceiverSession() => (PresentationSessionInfo? session_info);
 };
 
 interface PresentationServiceClient {