Cast channel: Add cast.channel.getLogs extension API.

extensions/common/api/cast_channel.idl

Index: extensions/common/api/cast_channel.idl
diff --git a/extensions/common/api/cast_channel.idl b/extensions/common/api/cast_channel.idl
index ebefa990cc7eb0e7cce249a8f5271f9e57256bf9..89a3190d971a80dabf6fd55e23cd01b4bdfd47d1 100644
--- a/extensions/common/api/cast_channel.idl
+++ b/extensions/common/api/cast_channel.idl
@@ -127,6 +127,13 @@ namespace cast.channel {
   // Callback holding the result of a channel operation.
   callback ChannelInfoCallback = void (ChannelInfo result);
 
+  // Callback from <code>getLogs</code> method.
+  // |log|: compressed serialized raw bytes containing the logs.
+  // The log is formatted using protocol buffer.
+  // See extensions/browser/api/cast_channel/logging.proto for definition.
+  // Compression is in gzip format.
+  callback GetLogsCallback = void (ArrayBuffer log);
+  
   interface Functions {
     // Opens a new channel to the Cast receiver specified by connectInfo.  Only
     // one channel may be connected to same receiver from the same extension at
@@ -155,6 +162,12 @@ namespace cast.channel {
     // and channel.errorState will be set to the error condition.
     static void close(ChannelInfo channel,
                       ChannelInfoCallback callback);
+      
+    // Get logs in compressed serialized format. See GetLogsCallback for
+    // details.  
+    // |callback|: If successful, |callback| is invoked with data. Otherwise,
+    // it is invoked with an empty ArrayBuffer.                

[mark a. foltz, 2014/08/11 23:01:44]

I think the preferred approach is to use chrome.runtime.lastError to report
errors instead.  See the examples in other API functions.

[imcheng, 2014/08/12 07:42:10]

Done. I assume this is done using SetError()? Is the new comment accurate?

+    static void getLogs(GetLogsCallback callback);
   };
 
   // Events on the channel.