Replace MockFilterCallback with MockCallback and simplify unit tests.

media/base/mock_filters.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/base/mock_filters.h"
 
 namespace media {
 
-MockFilterCallback::MockFilterCallback() : run_destroy_callback_(true) {}
-
-MockFilterCallback::MockFilterCallback(bool run_destroy_callback) :
-    run_destroy_callback_(run_destroy_callback) {
-}
-
-MockFilterCallback::~MockFilterCallback() {}
-
-FilterCallback* MockFilterCallback::NewCallback() {
-  return new CallbackImpl(this, run_destroy_callback_);
-}
-
 MockDataSource::MockDataSource() {}
 
 MockDataSource::~MockDataSource() {}
 
 MockDemuxer::MockDemuxer() {}
 
 MockDemuxer::~MockDemuxer() {}
 
 MockDemuxerStream::MockDemuxerStream() {}
 
@@ skipping 68 matching lines @@
 bool MockFilter::requires_message_loop() const {
   return requires_message_loop_;
 }
 
 const char* MockFilter::message_loop_name() const {
   return "MockFilter";
 }
 
 
 }  // namespace media