Added combined test for Syncable File System to write file and then get that usage gets updated.

chrome/browser/extensions/api/sync_file_system/sync_file_system_apitest.cc

 // 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.
 
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/sync_file_system/local_change_processor.h"
 #include "chrome/browser/sync_file_system/mock_remote_file_sync_service.h"
 #include "chrome/browser/sync_file_system/sync_file_system_service.h"
@@ skipping 39 matching lines @@
   }
 
  private:
   extensions::Feature::ScopedCurrentChannel current_channel_;
   ::testing::NiceMock<MockRemoteFileSyncService>* mock_remote_service_;
   int64 real_default_quota_;
 };
 
 }  // namespace
 
+// TODO(calvinlo): Add Chrome OS support for syncable file system
+#if !defined(OS_CHROMEOS)
+
 // TODO(benwells): Re-enable this test.
 IN_PROC_BROWSER_TEST_F(SyncFileSystemApiTest, DISABLED_DeleteFileSystem) {
   ASSERT_TRUE(RunPlatformAppTest("sync_file_system/delete_file_system"))
       << message_;
 }
 
 IN_PROC_BROWSER_TEST_F(SyncFileSystemApiTest, GetUsageAndQuota) {
   ASSERT_TRUE(RunExtensionTest("sync_file_system/get_usage_and_quota"))
       << message_;
 }
 
 IN_PROC_BROWSER_TEST_F(SyncFileSystemApiTest, RequestFileSystem) {
   EXPECT_CALL(*mock_remote_service(),
               RegisterOriginForTrackingChanges(_, _)).Times(1);
   ASSERT_TRUE(RunPlatformAppTest("sync_file_system/request_file_system"))
       << message_;
 }
 
+IN_PROC_BROWSER_TEST_F(SyncFileSystemApiTest, WriteFileThenGetUsage) {
+  ASSERT_TRUE(RunPlatformAppTest("sync_file_system/write_file_then_get_usage"))
+      << message_;
+}
+
+#endif  // !defined(OS_CHROMEOS)
+
 }  // namespace chrome
+