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

chrome/browser/chromeos/file_system_provider/fileapi/file_stream_reader_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_reader.h"
 
 #include <string>
 #include <vector>
 
 #include "base/files/file.h"
@@ skipping 78 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);
     FakeProvidedFileSystem* provided_file_system =
         static_cast<FakeProvidedFileSystem*>(
             service->GetProvidedFileSystem(kExtensionId, kFileSystemId));
     ASSERT_TRUE(provided_file_system);
     fake_file_ = provided_file_system->GetEntry(
         base::FilePath::FromUTF8Unsafe(kFakeFilePath));
     ASSERT_TRUE(fake_file_);
     const ProvidedFileSystemInfo& file_system_info =
         service->GetProvidedFileSystem(kExtensionId, kFileSystemId)
             ->GetFileSystemInfo();
@@ skipping 250 matching lines @@
   EXPECT_EQ(net::ERR_IO_PENDING, result);
   base::RunLoop().RunUntilIdle();
 
   ASSERT_EQ(1u, logger.results().size());
   EXPECT_LT(0, logger.results()[0]);
   EXPECT_EQ(fake_file_->metadata->size, logger.results()[0]);
 }
 
 }  // namespace file_system_provider
 }  // namespace chromeos