components: Cleanup class/struct fwd declarations

components/update_client/component_patcher_unittest.h

 // Copyright 2013 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.
 
 #ifndef COMPONENTS_UPDATE_CLIENT_COMPONENT_PATCHER_UNITTEST_H_
 #define COMPONENTS_UPDATE_CLIENT_COMPONENT_PATCHER_UNITTEST_H_
 
 #include <memory>
 
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/message_loop/message_loop.h"
 #include "courgette/courgette.h"
 #include "courgette/third_party/bsdiff/bsdiff.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace update_client {
 
-class MockComponentPatcher;
 class ReadOnlyTestInstaller;
 
 const char binary_output_hash[] =
     "599aba6d15a7da390621ef1bacb66601ed6aed04dadc1f9b445dcfe31296142a";
 
 class ComponentPatcherOperationTest : public testing::Test {
  public:
   ComponentPatcherOperationTest();
   ~ComponentPatcherOperationTest() override;
 
  protected:
   base::ScopedTempDir input_dir_;
   base::ScopedTempDir installed_dir_;
   base::ScopedTempDir unpack_dir_;
   scoped_refptr<ReadOnlyTestInstaller> installer_;
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 
  private:
   base::MessageLoopForIO loop_;
 };
 
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_COMPONENT_PATCHER_UNITTEST_H_