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

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 52b1cd7b24b4d6d8bc37591a2c52a762b247f5af..4ceb7caa5f9932ce995adb4c55fd0869ed2d8cf7 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -3237,6 +3237,10 @@ void RenderFrameImpl::willSendRequest(
             frame->top()->document().firstPartyForCookies());
       }
     }
+
+    // If the first-party isn't set, we need to set the first-party state as

[estark, 2015/10/20 23:41:58]

This comment isn't parsing for me. Is it possible that "first-party state" is
supposed to say "requestor origin" or something like that? Or is that what
first-party state means? I guess what I'm saying is that I'm confused. :)

[Mike West, 2015/10/22 13:17:02]

Yup. I can't type, obviously. Fixing the comment.

+    // well; it will not be updated during redirects.
+    request.setRequestorOrigin(frame->document().securityOrigin());
   }
 
   WebDataSource* provisional_data_source = frame->provisionalDataSource();