Add chrome/browser/apps/BUILD.gn and move Chrome-specific code there

apps/saved_files_service.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 APPS_SAVED_FILES_SERVICE_H_
 #define APPS_SAVED_FILES_SERVICE_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 83 matching lines @@
   std::vector<SavedFileEntry> GetAllFileEntries(
       const std::string& extension_id);
 
   // Clears all retained files if the app does not have the
   // fileSystem.retainEntries permission.
   void ClearQueueIfNoRetainPermission(const extensions::Extension* extension);
 
   // Clears all retained files.
   void ClearQueue(const extensions::Extension* extension);
 
+  // Called to notify that the application has begun to exit.
+  void OnApplicationTerminating();
+
  private:
   FRIEND_TEST_ALL_PREFIXES(::SavedFilesServiceUnitTest, RetainTwoFilesTest);
   FRIEND_TEST_ALL_PREFIXES(::SavedFilesServiceUnitTest, EvictionTest);
   FRIEND_TEST_ALL_PREFIXES(::SavedFilesServiceUnitTest,
                            SequenceNumberCompactionTest);
   friend class ::SavedFilesServiceUnitTest;
 
   // A container for the registered files for an app.
   class SavedFiles;
 
@@ skipping 20 matching lines @@
       extension_id_to_saved_files_;
   content::NotificationRegistrar registrar_;
   content::BrowserContext* context_;
 
   DISALLOW_COPY_AND_ASSIGN(SavedFilesService);
 };
 
 }  // namespace apps
 
 #endif  // APPS_SAVED_FILES_SERVICE_H_