Pepper: Add a X-Requested-With header to URL requests done for Pepper plugins.

webkit/support/webkit_support.cc

Index: webkit/support/webkit_support.cc
diff --git a/webkit/support/webkit_support.cc b/webkit/support/webkit_support.cc
index 94a1c8f57c25abeed4025009c7bf7ff959bcdb32..ef7e2eec0f851daa3e6e430f1b2176577a7df11f 100644
--- a/webkit/support/webkit_support.cc
+++ b/webkit/support/webkit_support.cc
@@ -780,6 +780,7 @@ WebKit::WebURLError CreateCancelledError(const WebKit::WebURLRequest& request) {
 WebKit::WebURLRequest::ExtraData* CreateWebURLRequestExtraData(
     WebKit::WebReferrerPolicy referrer_policy) {
   return new webkit_glue::WebURLRequestExtraDataImpl(referrer_policy,
+                                                     WebKit::WebString(),
                                                      WebKit::WebString());
 }