[fsp] Polish FakeProvidedFileSystem methods.

chrome/browser/chromeos/file_system_provider/fake_provided_file_system.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/fake_provided_file_system.h"
 
 #include <string>
 
 #include "base/files/file.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ skipping 130 matching lines @@
             callback, base::File::FILE_OK, entry_list, false /* has_more */));
   }
 }
 
 void FakeProvidedFileSystem::OpenFile(const base::FilePath& file_path,
                                       OpenFileMode mode,
                                       bool create,
                                       const OpenFileCallback& callback) {
   if (file_path.AsUTF8Unsafe() != "/hello.txt" ||
       mode == OPEN_FILE_MODE_WRITE || create) {
-    callback.Run(0 /* file_handle */, base::File::FILE_ERROR_SECURITY);
+    base::MessageLoopProxy::current()->PostTask(
+        FROM_HERE,
+        base::Bind(
+            callback, 0 /* file_handle */, base::File::FILE_ERROR_SECURITY));
     return;
   }
 
   const int file_handle = ++last_file_handle_;
   opened_files_[file_handle] = file_path;
-  callback.Run(file_handle, base::File::FILE_OK);
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, file_handle, base::File::FILE_OK));
 }
 
 void FakeProvidedFileSystem::CloseFile(
     int file_handle,
     const fileapi::AsyncFileUtil::StatusCallback& callback) {
   const OpenedFilesMap::iterator opened_file_it =
       opened_files_.find(file_handle);
   if (opened_file_it == opened_files_.end()) {
     base::MessageLoopProxy::current()->PostTask(
         FROM_HERE, base::Bind(callback, base::File::FILE_ERROR_NOT_FOUND));
@@ skipping 21 matching lines @@
                    0 /* chunk_length */,
                    false /* has_next */,
                    base::File::FILE_ERROR_SECURITY));
     return;
   }
 
   // Send the response byte by byte.
   size_t current_offset = static_cast<size_t>(offset);
   size_t current_length = static_cast<size_t>(length);
 
-  // Reading behind EOF, is fine, it will just read 0 bytes.
-  if (current_offset > kFakeFileSize || !current_length) {
+  // Reading behind EOF is fine, it will just return 0 bytes.
+  if (current_offset >= kFakeFileSize || !current_length) {
     base::MessageLoopProxy::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    0 /* chunk_length */,
                    false /* has_next */,
                    base::File::FILE_OK));
   }
 
   while (current_offset < kFakeFileSize && current_length) {
     buffer->data()[current_offset - offset] = kFakeFileText[current_offset];
     const bool has_next =
         (current_offset + 1 < kFakeFileSize) && (current_length - 1);
-    callback.Run(1, has_next, base::File::FILE_OK);
+    base::MessageLoopProxy::current()->PostTask(
+        FROM_HERE,
+        base::Bind(
+            callback, 1 /* chunk_length */, has_next, base::File::FILE_OK));
     current_offset++;
     current_length--;
   }
 }
 
 const ProvidedFileSystemInfo& FakeProvidedFileSystem::GetFileSystemInfo()
     const {
   return file_system_info_;
 }
 
 RequestManager* FakeProvidedFileSystem::GetRequestManager() {
   NOTREACHED();
   return NULL;
 }
 
 ProvidedFileSystemInterface* FakeProvidedFileSystem::Create(
     extensions::EventRouter* event_router,
     const ProvidedFileSystemInfo& file_system_info) {
   return new FakeProvidedFileSystem(file_system_info);
 }
 
 base::WeakPtr<ProvidedFileSystemInterface>
 FakeProvidedFileSystem::GetWeakPtr() {
   return weak_ptr_factory_.GetWeakPtr();
 }
 
 }  // namespace file_system_provider
 }  // namespace chromeos