[Presentation API] Plumbing of |onstatechange| from the Mojo service to the public/platform

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 99ab552c37f40c542d3588b9c14c0189abb8df32..8de73168040d7c7706f5b46174e755aa3084ffc0 100644
--- a/content/common/presentation/presentation_service.mojom
+++ b/content/common/presentation/presentation_service.mojom
@@ -9,6 +9,11 @@ struct PresentationSessionInfo {
     string id;
 };
 
+enum PresentationSessionState {
+    CONNECTED,
+    DISCONNECTED
+};
+
 enum PresentationErrorType {
     NO_AVAILABLE_SCREENS,
     SESSION_REQUEST_CANCELLED,
@@ -72,4 +77,12 @@ interface PresentationService {
 
     // Called when closeSession() is called by the frame.
     CloseSession(string presentation_url, string presentation_id);
+
+    // Called when the frame is ready to process the next state
+    // change. Returns the last session state if it’s
+    // changed since the last time the callback was called. Might

[Peter Beverloo, 2015/03/20 19:13:39]

nit: advocating for 70-character line length limits rather than 80-character
ones? :)

[whywhat, 2015/03/24 19:20:57]

Copy paste from the doc about the Mojo interface. Docs are narrower than code.

+    // cause the event fired with the initial state change.
+    ListenForSessionStateChange()

[mark a. foltz, 2015/03/20 21:22:43]

GetSessionState() for consistency with GetScreenAvailability()?

[whywhat, 2015/03/24 19:20:57]

But this is consistent with ListenForDefaultSessionStart. Probably should change
GetScreenAvailability to ListenForScreenAvailability in a separate CL?

[mark a. foltz, 2015/03/24 22:53:34]

SGTM

+        => (PresentationSessionInfo sessionInfo,
+            PresentationSessionState newState);
 };