Add WebMediaPlayer::timelineOffset() support to WebMediaPlayerImpl.

media/base/stream_parser.h

Index: media/base/stream_parser.h
diff --git a/media/base/stream_parser.h b/media/base/stream_parser.h
index c5410e3c385e9d801a30f791ff4f2133e5c35684..8123b4fc3d3deb3183261451e6b1f76ce9fea261 100644
--- a/media/base/stream_parser.h
+++ b/media/base/stream_parser.h
@@ -55,10 +55,15 @@ class MEDIA_EXPORT StreamParser {
   //                   occurred.
   // Second parameter - Indicates the stream duration. Only contains a valid
   //                    value if the first parameter is true.
-  // Third parameters - Indicates that timestampOffset should be updated based
+  // Third parameter - Indicates the Time associated with
+  //                   presentation timestamp 0 if such a mapping exists in
+  //                   the bytestream. If no mapping exists this parameter
+  //                   contains null Time object. Only contains a valid
+  //                   value if the first parameter is true.
+  // Fourth parameters - Indicates that timestampOffset should be updated based
   //                    on the earliest end timestamp (audio or video) provided
   //                    during each NewBuffersCB.
-  typedef base::Callback<void(bool, base::TimeDelta, bool)> InitCB;
+  typedef base::Callback<void(bool, base::TimeDelta, base::Time, bool)> InitCB;
 
   // Indicates when new stream configurations have been parsed.
   // First parameter - The new audio configuration. If the config is not valid