Migrates legacy packaged app data when it's upgraded to a platform app

storage/browser/fileapi/sandbox_file_system_backend_delegate.cc

 // 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.
 
 #include "storage/browser/fileapi/sandbox_file_system_backend_delegate.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
@@ skipping 630 matching lines @@
       REPORT(kNotFound);
       break;
     case base::File::FILE_ERROR_FAILED:
     default:
       REPORT(kUnknownError);
       break;
   }
 #undef REPORT
 }
 
+void SandboxFileSystemBackendDelegate::CopyFileSystem(
+    const GURL& origin_url,
+    FileSystemType type,
+    SandboxFileSystemBackendDelegate* destination) {
+  DCHECK(file_task_runner()->RunsTasksOnCurrentThread());
+
+  base::FilePath base_path =
+      GetBaseDirectoryForOriginAndType(origin_url, type, false /* create */);
+  if (base::PathExists(base_path)) {
+    // Delete any existing file system directories in the destination. A
+    // previously failed migration
+    // may have left behind partially copied directories.
+    base::FilePath dest_path = destination->GetBaseDirectoryForOriginAndType(
+        origin_url, type, false /* create */);
+    if (base::PathExists(dest_path)) {

[cmumford, 2015/01/06 15:30:27]

Consider disposing of the exists check and just call DeleteFile ignoring the
result.

+      // Make sure we're not about to delete our own file system.
+      CHECK(base_path != dest_path);

[cmumford, 2015/01/06 15:30:27]

CHECK_NE

+      base::DeleteFile(dest_path, true);
+    }
+
+    // Create the required path in the destination
+    dest_path = destination->GetBaseDirectoryForOriginAndType(
+        origin_url, type, true /* create */);
+
+    obfuscated_file_util()->CloseFileSystemForOriginAndType(
+        origin_url, GetTypeString(type));
+    base::CopyDirectory(base_path, dest_path.DirName(), true /* rescursive */);
+  }
+}
+
 ObfuscatedFileUtil* SandboxFileSystemBackendDelegate::obfuscated_file_util() {
   return static_cast<ObfuscatedFileUtil*>(sync_file_util());
 }
 
 // Declared in obfuscated_file_util.h.
 // static
 ObfuscatedFileUtil* ObfuscatedFileUtil::CreateForTesting(
     storage::SpecialStoragePolicy* special_storage_policy,
     const base::FilePath& file_system_directory,
     leveldb::Env* env_override,
     base::SequencedTaskRunner* file_task_runner) {
   return new ObfuscatedFileUtil(special_storage_policy,
                                 file_system_directory,
                                 env_override,
                                 file_task_runner,
                                 base::Bind(&GetTypeStringForURL),
                                 GetKnownTypeStrings(),
                                 NULL);
 }
 
 }  // namespace storage