Cast: Add JS API to get raw events logs from cast extension.

chrome/common/extensions/api/cast_streaming_rtp_stream.idl

 // Copyright 2013 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.
 
 // The <code>chrome.cast.streaming.rtpStream</code> API allows configuration
 // of encoding parameters and RTP parameters used in a Cast streaming
 // session.
 namespace cast.streaming.rtpStream {
   // Params for audio and video codec.
   dictionary CodecSpecificParams {
@@ skipping 42 matching lines @@
     // RTP payload params.
     RtpPayloadParams payload;
 
     DOMString[] rtcpFeatures;
   };
 
   // Callback from the <code>create</code> method.
   // |id| : The ID for the RTP stream.
   callback CreateCallback = void (long streamId);
 
+  // Callback from the <code>getRawEvents</code> method.
+  // |rawEvents|: events encoded in protocol buffer format along with other 

[not at google - send to devlin, 2014/02/25 19:34:36]

encoded in protobuf? like the raw bytes? or are you unwrapping it into its real
key/values?

[imcheng, 2014/02/25 21:00:51]

The events will be in serialized format as specified by protobuf library, so it
will be raw bytes. The exact format of the overall string is TBD because there
will be additional metadata in addition to just the events. I changed the
comments a bit. The specification of the format can be found at the cc file
mentioned here.

[not at google - send to devlin, 2014/02/25 21:03:46]

It's a bit crazy to expect extensions in the wild to include a protobuf parsing
library in order to use this API. It's reasonable for the wire format to be
protos but as a developer-facing API could you unwrap it into key-value?

+  // data serialized as a string.
+  // The serialization format can be found at 
+  // media/cast/logging/log_serializer.cc.
+  callback GetRawEventsCallback = void (DOMString rawEvents);
+  
+  // Callback from the <code>getStats</code> method.
+  // |rawEvents|: stats encoded in protocol buffer format along with other 
+  // data serialized as a string.
+  // The serialization format can be found at 
+  // media/cast/logging/log_serializer.cc.
+  callback GetStatsCallback = void (DOMString stats);
+
   interface Functions {
     // Destroys a Cast RTP stream.
     // |streamId| : The RTP stream ID.
     [nocompile] static void destroy(long streamId);
 
     // Returns an array of supported parameters with default values.
     // This includes a list of supported codecs on this platform and
     // corresponding encoding and RTP parameters.
     // |streamId| : The RTP stream ID.
     [nocompile] static RtpParams[] getSupportedParams(long streamId);
 
     // Activates the RTP stream by providing the parameters.
     // |streamId| : The RTP stream ID.
     // |params| : Parameters set for this stream.
     [nocompile] static void start(long streamId, RtpParams params);
 
     // Stops activity on the specified stream.
     // |streamId| : The RTP stream ID.
     [nocompile] static void stop(long streamId);
+
+    // Enables / disables logging for a stream.
+    // |enable|: If true, enables logging. Otherwise disables logging.
+    [nocompile] static void toggleLogging(long streamId, boolean enable);
+    
+    // Get raw events for a stream in the current session.
+    // |startLogging()| must have been called before.
+    // |streamId|: Stream to get events for.
+    // |callback|: Called with the raw events Blob.
+    [nocompile] static void getRawEvents(

[not at google - send to devlin, 2014/02/25 19:34:36]

how big could this be? can you limit it?

[imcheng, 2014/02/25 21:00:51]

Currently it is limited is 20MB. This will be smaller when we start to compress
the string before returning it to JS (~7 MB). The limit is subject to change but
won't be too large.

+        long streamId, GetRawEventsCallback callback);
+    
+    // Get stats for a stream in the current session.
+    // |startLogging()| must have been called before.
+    // |streamId|: Stream to get stats for.
+    // |callback|: Called with the stats Blob.
+    [nocompile] static void getStats(
+        long streamId, GetStatsCallback callback);
   };
 
   interface Events {
     // Event fired when a Cast RTP stream has started.
     // |streamId| : The ID of the RTP stream.
     static void onStarted(long streamId);
 
     // Event fired when a Cast RTP stream has stopped.
     // |streamId| : The ID of the RTP stream.
     static void onStopped(long streamId);
 
     // Event fired when a Cast RTP stream has error.
     // |streamId| : The ID of the RTP stream.
     // |errorString| : The error info.
     static void onError(long streamId, DOMString errorString);
   };
 };