Make ResourceHandler::OnWillRead able to complete asynchronously.

content/browser/loader/stream_resource_handler.h

Index: content/browser/loader/stream_resource_handler.h
diff --git a/content/browser/loader/stream_resource_handler.h b/content/browser/loader/stream_resource_handler.h
index 9f69994b238790dae89ec2e18ce3c5fe0531e976..7c678fc4692511788e51c5ac4526925acc3d32a3 100644
--- a/content/browser/loader/stream_resource_handler.h
+++ b/content/browser/loader/stream_resource_handler.h
@@ -46,8 +46,9 @@ class StreamResourceHandler : public ResourceHandler {
                    std::unique_ptr<ResourceController> controller) override;
 
   // Create a new buffer to store received data.
-  bool OnWillRead(scoped_refptr<net::IOBuffer>* buf,
-                  int* buf_size) override;
+  void OnWillRead(scoped_refptr<net::IOBuffer>* buf,
+                  int* buf_size,
+                  std::unique_ptr<ResourceController> controller) override;
 
   // A read was completed, forward the data to the Stream.
   void OnReadCompleted(int bytes_read,