Make OperationID usable for error handling.

webkit/browser/fileapi/file_system_operation_runner.cc

 // Copyright 2013 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 "webkit/browser/fileapi/file_system_operation_runner.h"
 
 #include "base/bind.h"
 #include "net/url_request/url_request_context.h"
 #include "webkit/browser/fileapi/file_observers.h"
 #include "webkit/browser/fileapi/file_stream_writer.h"
 #include "webkit/browser/fileapi/file_system_context.h"
 #include "webkit/browser/fileapi/file_system_operation_impl.h"
 #include "webkit/browser/fileapi/file_writer_delegate.h"
 #include "webkit/common/blob/shareable_file_reference.h"
 
 namespace fileapi {
 
 typedef FileSystemOperationRunner::OperationID OperationID;
 
-const OperationID FileSystemOperationRunner::kErrorOperationID = -1;
-
 FileSystemOperationRunner::~FileSystemOperationRunner() {
 }
 
 void FileSystemOperationRunner::Shutdown() {
   operations_.Clear();
 }
 
 OperationID FileSystemOperationRunner::CreateFile(
     const FileSystemURL& url,
     bool exclusive,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForWrite(id, url);
+    operation->CreateFile(
+        url, exclusive,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForWrite(id, url);
-  operation->CreateFile(
-      url, exclusive,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::CreateDirectory(
     const FileSystemURL& url,
     bool exclusive,
     bool recursive,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForWrite(id, url);
+    operation->CreateDirectory(
+        url, exclusive, recursive,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForWrite(id, url);
-  operation->CreateDirectory(
-      url, exclusive, recursive,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::Copy(
     const FileSystemURL& src_url,
     const FileSystemURL& dest_url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(dest_url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForWrite(id, dest_url);
+    PrepareForRead(id, src_url);
+    operation->Copy(
+        src_url, dest_url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForWrite(id, dest_url);
-  PrepareForRead(id, src_url);
-  operation->Copy(
-      src_url, dest_url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::Move(
     const FileSystemURL& src_url,
     const FileSystemURL& dest_url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(dest_url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForWrite(id, dest_url);
+    PrepareForWrite(id, src_url);
+    operation->Move(
+        src_url, dest_url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForWrite(id, dest_url);
-  PrepareForWrite(id, src_url);
-  operation->Move(
-      src_url, dest_url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::DirectoryExists(
     const FileSystemURL& url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForRead(id, url);
+    operation->DirectoryExists(
+        url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForRead(id, url);
-  operation->DirectoryExists(
-      url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::FileExists(
     const FileSystemURL& url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForRead(id, url);
+    operation->FileExists(
+        url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForRead(id, url);
-  operation->FileExists(
-      url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::GetMetadata(
     const FileSystemURL& url,
     const GetMetadataCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error, base::PlatformFileInfo());
-    return kErrorOperationID;
+    DidGetMetadata(id, callback, error, base::PlatformFileInfo());
+  } else {
+    PrepareForRead(id, url);
+    operation->GetMetadata(
+        url,
+        base::Bind(&FileSystemOperationRunner::DidGetMetadata, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForRead(id, url);
-  operation->GetMetadata(
-      url,
-      base::Bind(&FileSystemOperationRunner::DidGetMetadata, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::ReadDirectory(
     const FileSystemURL& url,
     const ReadDirectoryCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error, std::vector<DirectoryEntry>(), false);
-    return kErrorOperationID;
+    DidReadDirectory(
+        id, callback, error, std::vector<DirectoryEntry>(), false);
+  } else {
+    PrepareForRead(id, url);
+    operation->ReadDirectory(
+        url,
+        base::Bind(&FileSystemOperationRunner::DidReadDirectory, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForRead(id, url);
-  operation->ReadDirectory(
-      url,
-      base::Bind(&FileSystemOperationRunner::DidReadDirectory, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::Remove(
     const FileSystemURL& url, bool recursive,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForWrite(id, url);
+    operation->Remove(
+        url, recursive,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForWrite(id, url);
-  operation->Remove(
-      url, recursive,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::Write(
     const net::URLRequestContext* url_request_context,
     const FileSystemURL& url,
     const GURL& blob_url,
     int64 offset,
     const WriteCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
+
   if (!operation) {
-    callback.Run(error, 0, true);
-    return kErrorOperationID;
+    DidWrite(id, callback, error, 0, true);
+    return id;
   }
 
   scoped_ptr<FileStreamWriter> writer(
       file_system_context_->CreateFileStreamWriter(url, offset));
   if (!writer) {
     // Write is not supported.
-    callback.Run(base::PLATFORM_FILE_ERROR_SECURITY, 0, true);
-    return kErrorOperationID;
+    DidWrite(id, callback, base::PLATFORM_FILE_ERROR_SECURITY, 0, true);
+    return id;
   }
 
   DCHECK(blob_url.is_valid());
   scoped_ptr<FileWriterDelegate> writer_delegate(
       new FileWriterDelegate(writer.Pass()));
   scoped_ptr<net::URLRequest> blob_request(url_request_context->CreateRequest(
       blob_url, writer_delegate.get()));
 
-  OperationID id = operations_.Add(operation);
   PrepareForWrite(id, url);
   operation->Write(
       url, writer_delegate.Pass(), blob_request.Pass(),
       base::Bind(&FileSystemOperationRunner::DidWrite, AsWeakPtr(),
                  id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::Truncate(
     const FileSystemURL& url, int64 length,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForWrite(id, url);
+    operation->Truncate(
+        url, length,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForWrite(id, url);
-  operation->Truncate(
-      url, length,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 void FileSystemOperationRunner::Cancel(
     OperationID id,
     const StatusCallback& callback) {
   FileSystemOperation* operation = operations_.Lookup(id);
   if (!operation) {
     // The operation is already finished; report that we failed to stop it.
     callback.Run(base::PLATFORM_FILE_ERROR_INVALID_OPERATION);
     return;
   }
   operation->Cancel(callback);
 }
 
 OperationID FileSystemOperationRunner::TouchFile(
     const FileSystemURL& url,
     const base::Time& last_access_time,
     const base::Time& last_modified_time,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    PrepareForWrite(id, url);
+    operation->TouchFile(
+        url, last_access_time, last_modified_time,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForWrite(id, url);
-  operation->TouchFile(
-      url, last_access_time, last_modified_time,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::OpenFile(
     const FileSystemURL& url,
     int file_flags,
     base::ProcessHandle peer_handle,
     const OpenFileCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error, base::kInvalidPlatformFileValue,
-                 base::Closure(), base::ProcessHandle());
-    return kErrorOperationID;
+    DidOpenFile(id, callback, error, base::kInvalidPlatformFileValue,
+                base::Closure(), base::ProcessHandle());
+    return id;
   }
-  OperationID id = operations_.Add(operation);
   if (file_flags &
       (base::PLATFORM_FILE_CREATE | base::PLATFORM_FILE_OPEN_ALWAYS |
        base::PLATFORM_FILE_CREATE_ALWAYS | base::PLATFORM_FILE_OPEN_TRUNCATED |
        base::PLATFORM_FILE_WRITE | base::PLATFORM_FILE_EXCLUSIVE_WRITE |
        base::PLATFORM_FILE_DELETE_ON_CLOSE |
        base::PLATFORM_FILE_WRITE_ATTRIBUTES)) {
     PrepareForWrite(id, url);
   } else {
     PrepareForRead(id, url);
   }
   operation->OpenFile(
       url, file_flags, peer_handle,
       base::Bind(&FileSystemOperationRunner::DidOpenFile, AsWeakPtr(),
                  id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::CreateSnapshotFile(
     const FileSystemURL& url,
     const SnapshotFileCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error, base::PlatformFileInfo(), base::FilePath(), NULL);
-    return kErrorOperationID;
+    DidCreateSnapshot(
+        id, callback, error, base::PlatformFileInfo(), base::FilePath(), NULL);
+  } else {
+    PrepareForRead(id, url);
+    operation->CreateSnapshotFile(
+        url,
+        base::Bind(&FileSystemOperationRunner::DidCreateSnapshot, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  PrepareForRead(id, url);
-  operation->CreateSnapshotFile(
-      url,
-      base::Bind(&FileSystemOperationRunner::DidCreateSnapshot, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::CopyInForeignFile(
     const base::FilePath& src_local_disk_path,
     const FileSystemURL& dest_url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(dest_url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    operation->CopyInForeignFile(
+        src_local_disk_path, dest_url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  operation->CopyInForeignFile(
-      src_local_disk_path, dest_url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::RemoveFile(
     const FileSystemURL& url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    operation->RemoveFile(
+        url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  operation->RemoveFile(
-      url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::RemoveDirectory(
     const FileSystemURL& url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    operation->RemoveDirectory(
+        url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  operation->RemoveDirectory(
-      url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::CopyFileLocal(
     const FileSystemURL& src_url,
     const FileSystemURL& dest_url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(src_url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    operation->CopyFileLocal(
+        src_url, dest_url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  operation->CopyFileLocal(
-      src_url, dest_url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 OperationID FileSystemOperationRunner::MoveFileLocal(
     const FileSystemURL& src_url,
     const FileSystemURL& dest_url,
     const StatusCallback& callback) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(src_url, &error);
+  OperationID id = operations_.Add(operation);
   if (!operation) {
-    callback.Run(error);
-    return kErrorOperationID;
+    DidFinish(id, callback, error);
+  } else {
+    operation->MoveFileLocal(
+        src_url, dest_url,
+        base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
+                   id, callback));
   }
-  OperationID id = operations_.Add(operation);
-  operation->MoveFileLocal(
-      src_url, dest_url,
-      base::Bind(&FileSystemOperationRunner::DidFinish, AsWeakPtr(),
-                 id, callback));
   return id;
 }
 
 base::PlatformFileError FileSystemOperationRunner::SyncGetPlatformPath(
     const FileSystemURL& url,
     base::FilePath* platform_path) {
   base::PlatformFileError error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       file_system_context_->CreateFileSystemOperation(url, &error);
   if (!operation)
     return error;
   return operation->SyncGetPlatformPath(url, platform_path);
 }
 
 FileSystemOperationRunner::FileSystemOperationRunner(
     FileSystemContext* file_system_context)
     : file_system_context_(file_system_context) {}
 
 void FileSystemOperationRunner::DidFinish(
     OperationID id,
     const StatusCallback& callback,
     base::PlatformFileError rv) {
-  callback.Run(rv);
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, rv));
   FinishOperation(id);
 }
 
 void FileSystemOperationRunner::DidGetMetadata(
     OperationID id,
     const GetMetadataCallback& callback,
     base::PlatformFileError rv,
     const base::PlatformFileInfo& file_info) {
-  callback.Run(rv, file_info);
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, rv, file_info));
   FinishOperation(id);
 }
 
 void FileSystemOperationRunner::DidReadDirectory(
     OperationID id,
     const ReadDirectoryCallback& callback,
     base::PlatformFileError rv,
     const std::vector<DirectoryEntry>& entries,
     bool has_more) {
-  callback.Run(rv, entries, has_more);
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, rv, entries, has_more));
   if (rv != base::PLATFORM_FILE_OK || !has_more)
     FinishOperation(id);
 }
 
 void FileSystemOperationRunner::DidWrite(
     OperationID id,
     const WriteCallback& callback,
     base::PlatformFileError rv,
     int64 bytes,
     bool complete) {
-  callback.Run(rv, bytes, complete);
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, rv, bytes, complete));
   if (rv != base::PLATFORM_FILE_OK || complete)
     FinishOperation(id);
 }
 
 void FileSystemOperationRunner::DidOpenFile(
     OperationID id,
     const OpenFileCallback& callback,
     base::PlatformFileError rv,
     base::PlatformFile file,
     const base::Closure& on_close_callback,
     base::ProcessHandle peer_handle) {
-  callback.Run(rv, file, on_close_callback, peer_handle);
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, rv, file, on_close_callback, peer_handle));
   FinishOperation(id);
 }
 
 void FileSystemOperationRunner::DidCreateSnapshot(
     OperationID id,
     const SnapshotFileCallback& callback,
     base::PlatformFileError rv,
     const base::PlatformFileInfo& file_info,
     const base::FilePath& platform_path,
     const scoped_refptr<webkit_blob::ShareableFileReference>& file_ref) {
-  callback.Run(rv, file_info, platform_path, file_ref);
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, rv, file_info, platform_path, file_ref));
   FinishOperation(id);
 }
 
 void FileSystemOperationRunner::PrepareForWrite(OperationID id,
                                                 const FileSystemURL& url) {
   if (file_system_context_->GetUpdateObservers(url.type())) {
     file_system_context_->GetUpdateObservers(url.type())->Notify(
         &FileUpdateObserver::OnStartUpdate, MakeTuple(url));
   }
   write_target_urls_[id].insert(url);
@@ skipping 18 matching lines @@
             &FileUpdateObserver::OnEndUpdate, MakeTuple(*iter));
       }
     }
     write_target_urls_.erase(found);
   }
   DCHECK(operations_.Lookup(id));
   operations_.Remove(id);
 }
 
 }  // namespace fileapi