Revert 96974 - Remove mock_ffmpeg and update media unittests.

media/filters/ffmpeg_glue.h

Index: media/filters/ffmpeg_glue.h
===================================================================
--- media/filters/ffmpeg_glue.h	(revision 96976)
+++ media/filters/ffmpeg_glue.h	(working copy)
@@ -32,15 +32,15 @@
 #include "base/memory/singleton.h"
 #include "base/synchronization/lock.h"
 
-struct URLProtocol;
-
 namespace media {
 
 class FFmpegURLProtocol {
  public:
-  FFmpegURLProtocol() {}
+  FFmpegURLProtocol() {
+  }
 
-  virtual ~FFmpegURLProtocol() {}
+  virtual ~FFmpegURLProtocol() {
+  }
 
   // Read the given amount of bytes into data, returns the number of bytes read
   // if successful, kReadError otherwise.
@@ -99,9 +99,6 @@
   typedef std::map<std::string, FFmpegURLProtocol*> ProtocolMap;
   ProtocolMap protocols_;
 
-  friend class FFmpegGlueTest;
-  static URLProtocol* url_protocol();
-
   DISALLOW_COPY_AND_ASSIGN(FFmpegGlue);
 };