Make ResourceHandler::OnWillRead able to complete asynchronously.

content/browser/loader/layered_resource_handler.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 "content/browser/loader/layered_resource_handler.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "content/browser/loader/resource_controller.h"
@@ skipping 29 matching lines @@
   next_handler_->OnResponseStarted(response, std::move(controller));
 }
 
 void LayeredResourceHandler::OnWillStart(
     const GURL& url,
     std::unique_ptr<ResourceController> controller) {
   DCHECK(next_handler_.get());
   next_handler_->OnWillStart(url, std::move(controller));
 }
 
-bool LayeredResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
-                                        int* buf_size) {
+void LayeredResourceHandler::OnWillRead(
+    scoped_refptr<net::IOBuffer>* buf,
+    int* buf_size,
+    std::unique_ptr<ResourceController> controller) {
   DCHECK(next_handler_.get());
-  return next_handler_->OnWillRead(buf, buf_size);
+  return next_handler_->OnWillRead(buf, buf_size, std::move(controller));
 }
 
 void LayeredResourceHandler::OnReadCompleted(
     int bytes_read,
     std::unique_ptr<ResourceController> controller) {
   DCHECK(next_handler_.get());
   next_handler_->OnReadCompleted(bytes_read, std::move(controller));
 }
 
 void LayeredResourceHandler::OnResponseCompleted(
     const net::URLRequestStatus& status,
     std::unique_ptr<ResourceController> controller) {
   DCHECK(next_handler_.get());
   next_handler_->OnResponseCompleted(status, std::move(controller));
 }
 
 void LayeredResourceHandler::OnDataDownloaded(int bytes_downloaded) {
   DCHECK(next_handler_.get());
   next_handler_->OnDataDownloaded(bytes_downloaded);
 }
 
 }  // namespace content