[Blink-FileAPI] Add the notification of update observer.

storage/browser/fileapi/file_system_operation_runner.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/file_system_operation_runner.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/stl_util.h"
 #include "net/url_request/url_request_context.h"
@@ skipping 384 matching lines @@
     const StatusCallback& callback) {
   base::File::Error error = base::File::FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(dest_url, &error);
   BeginOperationScoper scope;
   OperationHandle handle = BeginOperation(operation, scope.AsWeakPtr());
   if (!operation) {
     DidFinish(handle, callback, error);
     return handle.id;
   }
+  PrepareForWrite(handle.id, dest_url);
   operation->CopyInForeignFile(
       src_local_disk_path, dest_url,
       base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
                  handle, callback));
   return handle.id;
 }
 
 OperationID FileSystemOperationRunner::RemoveFile(
     const FileSystemURL& url,
     const StatusCallback& callback) {
@@ skipping 263 matching lines @@
       stray_cancel_callbacks_.find(id);
   if (found_cancel != stray_cancel_callbacks_.end()) {
     // This cancel has been requested after the operation has finished,
     // so report that we failed to stop it.
     found_cancel->second.Run(base::File::FILE_ERROR_INVALID_OPERATION);
     stray_cancel_callbacks_.erase(found_cancel);
   }
 }
 
 }  // namespace storage