Revert of Add the chrome.fileSystem.onVolumeListChanged event.

chrome/browser/extensions/api/file_system/file_system_api.h

 // Copyright (c) 2012 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_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 28 matching lines @@
 base::FilePath GetLastChooseEntryDirectory(const ExtensionPrefs* prefs,
                                            const std::string& extension_id);
 
 void SetLastChooseEntryDirectory(ExtensionPrefs* prefs,
                                  const std::string& extension_id,
                                  const base::FilePath& path);
 
 std::vector<base::FilePath> GetGrayListedDirectories();
 
 #if defined(OS_CHROMEOS)
-// Dispatches an event about a mounted on unmounted volume in the system to
-// each extension which can request it.
-void DispatchVolumeListChangeEvent(Profile* profile);
-
 // Requests consent for the chrome.fileSystem.requestFileSystem() method.
 // Interaction with UI and environmental checks (kiosk mode, whitelist) are
 // provided by a delegate: ConsentProviderDelegate. For testing, it is
 // TestingConsentProviderDelegate.
 class ConsentProvider {
  public:
   enum Consent { CONSENT_GRANTED, CONSENT_REJECTED, CONSENT_IMPOSSIBLE };
   typedef base::Callback<void(Consent)> ConsentCallback;
   typedef base::Callback<void(ui::DialogButton)> ShowDialogCallback;
 
@@ skipping 349 matching lines @@
   ExtensionFunction::ResponseAction Run() override;
 
  private:
   ChromeExtensionFunctionDetails chrome_details_;
 };
 #endif
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_