[Streams] Pass WebDataConsumerHandle when the response arrives.

public/platform/WebURLLoaderClient.h

Index: public/platform/WebURLLoaderClient.h
diff --git a/public/platform/WebURLLoaderClient.h b/public/platform/WebURLLoaderClient.h
index e3171b372c0bcb70edcf4cd56eabba92a1acde34..09ab9567a19e956b9115d2e9c4e0b402ead18008 100644
--- a/public/platform/WebURLLoaderClient.h
+++ b/public/platform/WebURLLoaderClient.h
@@ -31,6 +31,8 @@
 #ifndef WebURLLoaderClient_h
 #define WebURLLoaderClient_h
 
+#include "public/platform/WebDataConsumerHandle.h"
+
 namespace blink {
 
 class WebURLLoader;
@@ -53,6 +55,14 @@ public:
     // Called when response headers are received.
     virtual void didReceiveResponse(WebURLLoader*, const WebURLResponse&) { }
 
+    // Called when response headers are received.
+    // The ownership of |handle| is transferred to the callee.
+    virtual void didReceiveResponse(WebURLLoader* loader, const WebURLResponse& response, WebDataConsumerHandle* handle)
+    {
+        delete handle;
+        didReceiveResponse(loader, response);
+    }
+
     // Called when a chunk of response data is downloaded. This is only called
     // if WebURLRequest's downloadToFile flag was set to true.
     virtual void didDownloadData(WebURLLoader*, int dataLength, int encodedDataLength) { }