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

media/filters/decoder_base.h

Index: media/filters/decoder_base.h
diff --git a/media/filters/decoder_base.h b/media/filters/decoder_base.h
index 6cf49374b411036a2aca07e554904d731d0f24a4..a889e19fb1082de5d09b9c7062861b8d4d8efd91 100644
--- a/media/filters/decoder_base.h
+++ b/media/filters/decoder_base.h
@@ -34,11 +34,10 @@ class DecoderBase : public Decoder {
         NewRunnableMethod(this, &DecoderBase::StopTask, callback));
   }
 
-  virtual void Seek(base::TimeDelta time,
-                    FilterCallback* callback) {
+  virtual void Seek(base::TimeDelta time, const FilterStatusCB& cb) {
     message_loop_->PostTask(
         FROM_HERE,
-        NewRunnableMethod(this, &DecoderBase::SeekTask, time, callback));
+        NewRunnableMethod(this, &DecoderBase::SeekTask, time, cb));
   }
 
   // Decoder implementation.
@@ -170,25 +169,22 @@ class DecoderBase : public Decoder {
     }
   }
 
-  void SeekTask(base::TimeDelta time, FilterCallback* callback) {
+  void SeekTask(base::TimeDelta time, const FilterStatusCB& cb) {
     DCHECK_EQ(MessageLoop::current(), message_loop_);
     DCHECK_EQ(0u, pending_reads_) << "Pending reads should have completed";
     DCHECK_EQ(0u, pending_requests_) << "Pending requests should be empty";
 
     // Delegate to the subclass first.
-    DoSeek(time,
-           NewRunnableMethod(this, &DecoderBase::OnSeekComplete, callback));
+    DoSeek(time, NewRunnableMethod(this, &DecoderBase::OnSeekComplete, cb));
   }
 
-  void OnSeekComplete(FilterCallback* callback) {
+  void OnSeekComplete(const FilterStatusCB& cb) {
     // Flush our decoded results.
     result_queue_.clear();
 
     // Signal that we're done seeking.
-    if (callback) {
-      callback->Run();
-      delete callback;
-    }
+    if (!cb.is_null())
+      cb.Run(PIPELINE_OK);
   }
 
   void InitializeTask(DemuxerStream* demuxer_stream,