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

net/url_request/url_fetcher_core.h

Index: net/url_request/url_fetcher_core.h
diff --git a/net/url_request/url_fetcher_core.h b/net/url_request/url_fetcher_core.h
index ad40799a8370843a9f143f6931af334082ae867f..9b4bba2c53b7fc1d5ce6c01bd92dbefd50286172 100644
--- a/net/url_request/url_fetcher_core.h
+++ b/net/url_request/url_fetcher_core.h
@@ -87,9 +87,12 @@ class URLFetcherCore : public base::RefCountedThreadSafe<URLFetcherCore>,
   void SetExtraRequestHeaders(const std::string& extra_request_headers);
   void AddExtraRequestHeader(const std::string& header_line);
   void SetRequestContext(URLRequestContextGetter* request_context_getter);
-  // Set the URL that should be consulted for the third-party cookie
-  // blocking policy.
-  void SetFirstPartyForCookies(const GURL& first_party_for_cookies);
+  // Set the URL that should be considered as "initiating" the fetch. This URL
+  // will be considered the "first-party" when applying cookie blocking policy
+  // to requests, and treated as the request's initiator.
+  //
+  // TODO(mkwst): Convert this to a url::Origin. https://crbug.com/577565
+  void SetInitiatorURL(const GURL& initiator);
   // Set the key and data callback that is used when setting the user
   // data on any URLRequest objects this object creates.
   void SetURLRequestUserData(
@@ -243,7 +246,7 @@ class URLFetcherCore : public base::RefCountedThreadSafe<URLFetcherCore>,
                                      // Read buffer
   scoped_refptr<URLRequestContextGetter> request_context_getter_;
                                      // Cookie/cache info for the request
-  GURL first_party_for_cookies_;     // The first party URL for the request
+  GURL initiator_;  // The request's initiator
   // The user data to add to each newly-created URLRequest.
   const void* url_request_data_key_;
   URLFetcher::CreateDataCallback url_request_create_data_callback_;