Add buffering to MimeSniffingResourceHandler.

content/browser/loader/mojo_async_resource_handler.h

Index: content/browser/loader/mojo_async_resource_handler.h
diff --git a/content/browser/loader/mojo_async_resource_handler.h b/content/browser/loader/mojo_async_resource_handler.h
index 57198253f79079312d11140009f7688ffa53a51e..194425c686e216b6d1d26d0c08f6c2fcebd36f83 100644
--- a/content/browser/loader/mojo_async_resource_handler.h
+++ b/content/browser/loader/mojo_async_resource_handler.h
@@ -131,11 +131,9 @@ class CONTENT_EXPORT MojoAsyncResourceHandler
 
   bool has_checked_for_sufficient_resources_ = false;
   bool sent_received_response_message_ = false;
-  bool is_using_io_buffer_not_from_writer_ = false;
   // True if OnWillRead was deferred, in order to wait to be able to allocate a
   // buffer.
   bool did_defer_on_will_read_ = false;
-  bool did_defer_on_writing_ = false;
   bool did_defer_on_redirect_ = false;
   base::TimeTicks response_started_ticks_;
   int64_t reported_total_received_bytes_ = 0;