Pepper: Add a property to URLRequestInfo to skip header validation.

ppapi/cpp/url_request_info.h

Index: ppapi/cpp/url_request_info.h
diff --git a/ppapi/cpp/url_request_info.h b/ppapi/cpp/url_request_info.h
index 3c7c47d130ea3e78549cb7121006ad40993de511..c1cda4ebe1c33140e5d2b052c5bf05e52a9352ad 100644
--- a/ppapi/cpp/url_request_info.h
+++ b/ppapi/cpp/url_request_info.h
@@ -51,6 +51,10 @@ class URLRequestInfo : public Resource {
   bool SetRecordUploadProgress(bool enable) {
     return SetProperty(PP_URLREQUESTPROPERTY_RECORDUPLOADPROGRESS, enable);
   }
+  // To use the default referrer, set url_string to an Undefined Var.
+  bool SetCustomReferrerURL(const Var& url_string) {
+    return SetProperty(PP_URLREQUESTPROPERTY_CUSTOMREFERRERURL, url_string);
+  }
 };
 
 }  // namespace pp