Remove thread restriction of fileapi::FileSystemContext::ResolveURL.

webkit/browser/fileapi/file_system_context.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 "webkit/browser/fileapi/file_system_context.h"
 
 #include "base/bind.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/task_runner_util.h"
@@ skipping 39 matching lines @@
     const FileSystemInfo& info,
     base::File::Error error,
     const base::File::Info& file_info) {
   if (error != base::File::FILE_OK) {
     callback.Run(error, FileSystemInfo(), base::FilePath(), false);
     return;
   }
   callback.Run(error, info, path, file_info.is_directory);
 }
 
+void RelayResolveURLCallback(
+    scoped_refptr<base::MessageLoopProxy> message_loop,
+    const FileSystemContext::ResolveURLCallback& callback,
+    base::File::Error result,
+    const FileSystemInfo& info,
+    const base::FilePath& file_path,
+    bool is_directory) {
+  message_loop->PostTask(
+      FROM_HERE,
+      base::Bind(callback, result, info, file_path, is_directory));
+}
+
 }  // namespace
 
 // static
 int FileSystemContext::GetPermissionPolicy(FileSystemType type) {
   switch (type) {
     case kFileSystemTypeTemporary:
     case kFileSystemTypePersistent:
     case kFileSystemTypeSyncable:
       return FILE_PERMISSION_SANDBOX;
 
@@ skipping 245 matching lines @@
 
   backend->ResolveURL(
       CreateCrackedFileSystemURL(origin_url, type, base::FilePath()),
       mode,
       callback);
 }
 
 void FileSystemContext::ResolveURL(
     const FileSystemURL& url,
     const ResolveURLCallback& callback) {
-  // TODO(nhiroki, kinuko): Remove this thread restriction, so it can be called
-  // on either UI or IO thread.
-  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(!callback.is_null());
 
+  // If not on IO thread, forward before passing the task to the backend.
+  if (!io_task_runner_->RunsTasksOnCurrentThread()) {
+    ResolveURLCallback relay_callback =
+        base::Bind(&RelayResolveURLCallback,
+                   base::MessageLoopProxy::current(), callback);
+    io_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&FileSystemContext::ResolveURL, this, url, relay_callback));
+    return;
+  }
+
   FileSystemBackend* backend = GetFileSystemBackend(url.type());
   if (!backend) {
     callback.Run(base::File::FILE_ERROR_SECURITY,
                  FileSystemInfo(), base::FilePath(), false);
     return;
   }
 
   backend->ResolveURL(
       url,
       OPEN_FILE_SYSTEM_FAIL_IF_NONEXISTENT,
@@ skipping 237 matching lines @@
   } else if (parent != child) {
     bool result = parent.AppendRelativePath(child, &path);
     DCHECK(result);
   }
 
   operation_runner()->GetMetadata(
       url, base::Bind(&DidGetMetadataForResolveURL, path, callback, info));
 }
 
 }  // namespace fileapi