Make ResourceHandler::OnWillRead able to complete asynchronously.

content/browser/loader/sync_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/sync_resource_handler.h"
 
 #include "base/callback_helpers.h"
 #include "base/logging.h"
 #include "content/browser/loader/netlog_observer.h"
 #include "content/browser/loader/resource_controller.h"
@@ skipping 78 matching lines @@
   result_.devtools_info = response->head.devtools_info;
   controller->Resume();
 }
 
 void SyncResourceHandler::OnWillStart(
     const GURL& url,
     std::unique_ptr<ResourceController> controller) {
   controller->Resume();
 }
 
-bool SyncResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
-                                     int* buf_size) {
+void SyncResourceHandler::OnWillRead(
+    scoped_refptr<net::IOBuffer>* buf,
+    int* buf_size,
+    std::unique_ptr<ResourceController> controller) {
   *buf = read_buffer_.get();
   *buf_size = kReadBufSize;
-  return true;
+  controller->Resume();
 }
 
 void SyncResourceHandler::OnReadCompleted(
     int bytes_read,
     std::unique_ptr<ResourceController> controller) {
   if (bytes_read)
     result_.data.append(read_buffer_->data(), bytes_read);
   controller->Resume();
 }
 
@@ skipping 10 matching lines @@
 
   controller->Resume();
 }
 
 void SyncResourceHandler::OnDataDownloaded(int bytes_downloaded) {
   // Sync requests don't involve ResourceMsg_DataDownloaded messages
   // being sent back to renderers as progress is made.
 }
 
 }  // namespace content