Make MediaFileUtil run on thread pool.

webkit/fileapi/isolated_mount_point_provider.cc

Index: webkit/fileapi/isolated_mount_point_provider.cc
diff --git a/webkit/fileapi/isolated_mount_point_provider.cc b/webkit/fileapi/isolated_mount_point_provider.cc
index 7e66106949bf6ded23544e23b6304ec346cb09b6..601c9de6679531aaf180befb8f4ca8a860ffa408 100644
--- a/webkit/fileapi/isolated_mount_point_provider.cc
+++ b/webkit/fileapi/isolated_mount_point_provider.cc
@@ -35,8 +35,10 @@ IsolatedContext* isolated_context() {
 
 }  // namespace
 
-IsolatedMountPointProvider::IsolatedMountPointProvider()
+IsolatedMountPointProvider::IsolatedMountPointProvider(
+    base::SequencedTaskRunner* media_task_runner)
     : media_path_filter_(new MediaPathFilter()),
+      media_task_runner_(media_task_runner),
       isolated_file_util_(new IsolatedFileUtil()),
       dragged_file_util_(new DraggedFileUtil()),
       native_media_file_util_(new NativeMediaFileUtil()) {
@@ -113,8 +115,10 @@ IsolatedMountPointProvider::CreateFileSystemOperation(
   scoped_ptr<FileSystemOperationContext> operation_context(
       new FileSystemOperationContext(context));
   if (url.type() == kFileSystemTypeNativeMedia ||
-      url.type() == kFileSystemTypeDeviceMedia)
+      url.type() == kFileSystemTypeDeviceMedia) {
     operation_context->set_media_path_filter(media_path_filter_.get());
+    operation_context->SetTaskRunner(media_task_runner_.get());
+  }
   return new LocalFileSystemOperation(context, operation_context.Pass());
 }