Teach URLRequest about initiator checks for First-Party-Only cookies.

content/child/request_info.h

Index: content/child/request_info.h
diff --git a/content/child/request_info.h b/content/child/request_info.h
index 037c1db059a588968cec13d67e16985a62b38948..e83d636c934202807528c5fba732a34b227c4930 100644
--- a/content/child/request_info.h
+++ b/content/child/request_info.h
@@ -20,6 +20,7 @@
 #include "third_party/WebKit/public/platform/WebTaskRunner.h"
 #include "third_party/WebKit/public/platform/WebURLRequest.h"
 #include "url/gurl.h"
+#include "url/origin.h"
 
 namespace blink {
 class WebTaskRunner;
@@ -38,10 +39,13 @@ struct CONTENT_EXPORT RequestInfo {
   // Absolute URL encoded in ASCII per the rules of RFC-2396.
   GURL url;
 
-  // URL of the document in the top-level window, which may be checked by the
-  // third-party cookie blocking policy.
+  // URL representing the first-party origin for the request, which may be
+  // checked by the third-party cookie blocking policy.
   GURL first_party_for_cookies;
 
+  // The origin of the context which initiated the request.
+  url::Origin request_initiator;
+
   // Optional parameter, the referrer to use for the request for the url member.
   Referrer referrer;