Add update observer to file_system_operation_impl_unittest for

content/browser/fileapi/mock_file_update_observer.cc

+// Copyright 2014 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 "base/thread_task_runner_handle.h"
+#include "content/browser/fileapi/mock_file_update_observer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace storage {
+
+MockFileUpdateObserver::MockFileUpdateObserver() : is_ready_(false) {
+}
+
+MockFileUpdateObserver::~MockFileUpdateObserver() {
+}
+
+// static
+UpdateObserverList MockFileUpdateObserver::CreateList(
+    MockFileUpdateObserver* observer) {
+  UpdateObserverList list;
+  return list.AddObserver(observer, base::ThreadTaskRunnerHandle::Get().get());
+}
+
+void MockFileUpdateObserver::OnStartUpdate(const FileSystemURL& url) {
+  if (is_ready_)
+    ++start_update_count_[url];
+}
+
+void MockFileUpdateObserver::OnUpdate(const FileSystemURL& url, int64 delta) {
+  if (!is_ready_)
+    return;
+  int start = start_update_count_[url];
+  int end = end_update_count_[url];
+  EXPECT_LT(0, start - end);
+}
+
+void MockFileUpdateObserver::OnEndUpdate(const FileSystemURL& url) {
+  if (is_ready_)
+    ++end_update_count_[url];
+}
+
+}  // namespace storage