[BlobAsync] Renderer support for blob file writing.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index 14a536015a416aa9b86cebe1f0b6f2369baef218..31af5ac20a82fffa397158f5a0769ae17211ef93 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -665,7 +665,8 @@ void RenderThreadImpl::Init(
 
   media_stream_center_ = NULL;
 
-  blob_message_filter_ = new BlobMessageFilter();
+  blob_message_filter_ = new BlobMessageFilter(GetIOMessageLoopProxy(),
+                                               GetFileThreadMessageLoopProxy());
   AddFilter(blob_message_filter_.get());
   db_message_filter_ = new DBMessageFilter();
   AddFilter(db_message_filter_.get());