[fsp] Pass more detailed errors to the providing extension.

chrome/browser/chromeos/file_system_provider/fileapi/file_stream_writer_unittest.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 "chrome/browser/chromeos/file_system_provider/fileapi/file_stream_writer.h"
 
 #include <string>
 #include <vector>
 
 #include "base/files/file.h"
@@ skipping 62 matching lines @@
     profile_manager_.reset(
         new TestingProfileManager(TestingBrowserProcess::GetGlobal()));
     ASSERT_TRUE(profile_manager_->SetUp());
     profile_ = profile_manager_->CreateTestingProfile("testing-profile");
 
     ServiceFactory::GetInstance()->SetTestingFactory(profile_, &CreateService);
     Service* service = Service::Get(profile_);  // Owned by its factory.
     service->SetFileSystemFactoryForTesting(
         base::Bind(&FakeProvidedFileSystem::Create));
 
-    const bool result = service->MountFileSystem(
+    const base::File::Error result = service->MountFileSystem(
         kExtensionId, MountOptions(kFileSystemId, "Testing File System"));
-    ASSERT_TRUE(result);
+    ASSERT_EQ(base::File::FILE_OK, result);
     provided_file_system_ = static_cast<FakeProvidedFileSystem*>(
         service->GetProvidedFileSystem(kExtensionId, kFileSystemId));
     ASSERT_TRUE(provided_file_system_);
     const ProvidedFileSystemInfo& file_system_info =
         provided_file_system_->GetFileSystemInfo();
     const std::string mount_point_name =
         file_system_info.mount_path().BaseName().AsUTF8Unsafe();
 
     file_url_ = CreateFileSystemURL(
         mount_point_name, base::FilePath::FromUTF8Unsafe(kFakeFilePath + 1));
@@ skipping 130 matching lines @@
 
   ASSERT_EQ(1u, write_log.size());
   EXPECT_EQ(sizeof(kTextToWrite) - 1, static_cast<size_t>(write_log[0]));
 
   const std::string expected_contents = original_contents + kTextToWrite;
   EXPECT_EQ(expected_contents, entry->contents);
 }
 
 }  // namespace file_system_provider
 }  // namespace chromeos