Fix various MediaSource related crashes on Android.

media/base/android/media_source_player.cc

Index: media/base/android/media_source_player.cc
diff --git a/media/base/android/media_source_player.cc b/media/base/android/media_source_player.cc
index b29d182d84938638a33561467efe1f6dae3f4c9a..f6cbd48a2d8ed45de5c0ab768555af0882bc4c0d 100644
--- a/media/base/android/media_source_player.cc
+++ b/media/base/android/media_source_player.cc
@@ -208,7 +208,6 @@ MediaSourcePlayer::MediaSourcePlayer(
       waiting_for_audio_data_(false),
       waiting_for_video_data_(false),
       weak_this_(this) {
-  OnMediaMetadataChanged(duration_, width_, height_, false);

[qinmin, 2013/05/22 18:51:24]

thanks for doing this, i was about to upload a CL doing the same thing

 }
 
 MediaSourcePlayer::~MediaSourcePlayer() {
@@ -221,9 +220,11 @@ void MediaSourcePlayer::SetVideoSurface(jobject surface) {
     return;
   }
 
-  video_decoder_job_.reset(new VideoDecoderJob(
-      base::MessageLoopProxy::current(), video_codec_,
-      gfx::Size(width_, height_), surface));
+  if (HasVideo()) {
+    video_decoder_job_.reset(new VideoDecoderJob(
+        base::MessageLoopProxy::current(), video_codec_,
+        gfx::Size(width_, height_), surface));
+  }
 
   if (pending_play_)
     StartInternal();