Convert Filter::Seek() to use new callback system.

content/renderer/media/ipc_video_decoder.cc

Index: content/renderer/media/ipc_video_decoder.cc
diff --git a/content/renderer/media/ipc_video_decoder.cc b/content/renderer/media/ipc_video_decoder.cc
index 37f7983c2566dbf3a5b9b4d9978bdc42cb6e6f49..36de04d12fc950761e470ec65e4091a34e271876 100644
--- a/content/renderer/media/ipc_video_decoder.cc
+++ b/content/renderer/media/ipc_video_decoder.cc
@@ -102,8 +102,8 @@ void IpcVideoDecoder::Flush(media::FilterCallback* callback) {
 }
 
 void IpcVideoDecoder::Seek(base::TimeDelta time,
-                           media::FilterCallback* callback) {
-  seek_callback_.reset(callback);
+                           const media::FilterStatusCB& cb) {
+  seek_cb_ = cb;
   decode_engine_->Seek();
 }
 
@@ -155,8 +155,7 @@ void IpcVideoDecoder::OnFlushComplete() {
 
 void IpcVideoDecoder::OnSeekComplete() {
   DCHECK_EQ(ChildProcess::current()->io_message_loop(), MessageLoop::current());
-  seek_callback_->Run();
-  seek_callback_.reset();
+  CopyAndResetCB(seek_cb_).Run(media::PIPELINE_OK);
 }
 
 void IpcVideoDecoder::OnError() {