Add a copy or move validator to that can handle support audio and video files.

chrome/browser/media_galleries/fileapi/safe_audio_video_checker.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 CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_SAFE_AUDIO_VIDEO_CHECKER_H_
+#define CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_SAFE_AUDIO_VIDEO_CHECKER_H_
+
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
+#include "base/files/scoped_platform_file_closer.h"
+#include "base/memory/weak_ptr.h"
+#include "base/platform_file.h"
+#include "content/public/browser/utility_process_host_client.h"
+#include "webkit/browser/fileapi/copy_or_move_file_validator.h"
+
+namespace content {
+class UtilityProcessHost;
+}
+
+// Uses a utility process to validate a media file.  If the callback returns
+// PLATFORM_FILE_OK, then the file appears to be a valid media file. This does
+// not attempt to decode the entire file, which may take a considerable amount
+// of time.  This class may be constructed on any thread, but should run on the
+// IO thread.
+class SafeAudioVideoChecker : public content::UtilityProcessHostClient {
+ public:
+  // Takes responsibility for closing |file|.
+  SafeAudioVideoChecker(
+      const base::PlatformFile& file,
+      const fileapi::CopyOrMoveFileValidator::ResultCallback& callback);
+
+  // Must be called on the IO thread.
+  void Start();
+
+ private:
+  enum State {
+    INITIAL_STATE,
+    PINGED_STATE,
+    STARTED_STATE,
+    FINISHED_STATE
+  };
+
+  virtual ~SafeAudioVideoChecker();
+
+  // Starts validation once the utility process has been started.
+  virtual void OnProcessStarted();
+
+  // Notification of the result from the utility process.
+  void OnCheckingFinished(bool valid);
+
+  // UtilityProcessHostClient implementation.
+  virtual void OnProcessCrashed(int exit_code) OVERRIDE;
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  State state_;
+
+  // This should be accessed through |file_closer_| to ensure it hasn't already
+  // been closed.
+  base::PlatformFile file_;
+
+  // Ensures that |file_| is closed if the utility process is not started for
+  // some reason.
+  base::ScopedPlatformFileCloser file_closer_;
+
+  const fileapi::CopyOrMoveFileValidator::ResultCallback callback_;
+
+  base::WeakPtr<content::UtilityProcessHost> utility_process_host_;
+
+  DISALLOW_COPY_AND_ASSIGN(SafeAudioVideoChecker);
+};
+
+#endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_SAFE_AUDIO_VIDEO_CHECKER_H_