Adding callback support to media filter Initialize() and Seek().

media/base/filter_host.h

Index: media/base/filter_host.h
diff --git a/media/base/filter_host.h b/media/base/filter_host.h
index 4907df2af9ee84758a2ac3e63d825f4f58f42015..982b3e5aaa790ad0cc7f4cf2cd90ed8375eee140 100644
--- a/media/base/filter_host.h
+++ b/media/base/filter_host.h
@@ -24,11 +24,6 @@ namespace media {
 
 class FilterHost {
  public:
-  // Filters must call this method to indicate that their initialization is
-  // complete.  They may call this from within their Initialize() method or may
-  // choose call it after processing some data.
-  virtual void InitializationComplete() = 0;
-
   // Stops execution of the pipeline due to a fatal error.  Do not call this
   // method with PIPELINE_OK or PIPELINE_STOPPING (used internally by pipeline).
   virtual void Error(PipelineError error) = 0;