Fix classes that have too many virtuals for inline constructors.

components/drive/dummy_file_system.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_DRIVE_DUMMY_FILE_SYSTEM_H_
 #define COMPONENTS_DRIVE_DUMMY_FILE_SYSTEM_H_
 
 #include "components/drive/file_system_interface.h"
 
 namespace drive {
 
 // Dummy implementation of FileSystemInterface. All functions do nothing.
 class DummyFileSystem : public FileSystemInterface {
  public:
+  DummyFileSystem();
   ~DummyFileSystem() override {}
   void AddObserver(FileSystemObserver* observer) override {}
   void RemoveObserver(FileSystemObserver* observer) override {}
   void CheckForUpdates() override {}
   void TransferFileFromLocalToRemote(
       const base::FilePath& local_src_file_path,
       const base::FilePath& remote_dest_file_path,
       const FileOperationCallback& callback) override {}
   void OpenFile(const base::FilePath& file_path,
                 OpenMode open_mode,
@@ skipping 77 matching lines @@
   void FreeDiskSpaceIfNeededFor(
       int64 num_bytes,
       const FreeDiskSpaceCallback& callback) override {}
   void CalculateEvictableCacheSize(
       const EvictableCacheSizeCallback& callback) override {}
 };
 
 }  // namespace drive
 
 #endif  // COMPONENTS_DRIVE_DUMMY_FILE_SYSTEM_H_