Rename NetworkDelegate first-party-only flag

Renames the NetworkDelegate flag to
AreExperimentalCookieFeaturesEnabled(). This is in preparation for adding
experimental support for cookie prefixes in
https://codereview.chromium.org/1393193005/.

BUG=541511

Review URL: https://codereview.chromium.org/1392853006

Cr-Commit-Position: refs/heads/master@{#353584}
diff --git a/net/base/layered_network_delegate.cc b/net/base/layered_network_delegate.cc
index d384d5ea..9652d1c 100644
--- a/net/base/layered_network_delegate.cc
+++ b/net/base/layered_network_delegate.cc
@@ -258,14 +258,13 @@
     const GURL& first_party_for_cookies) const {
 }
 
-bool LayeredNetworkDelegate::OnFirstPartyOnlyCookieExperimentEnabled() const {
-  OnFirstPartyOnlyCookieExperimentEnabledInternal();
-  return nested_network_delegate_->FirstPartyOnlyCookieExperimentEnabled();
+bool LayeredNetworkDelegate::OnAreExperimentalCookieFeaturesEnabled() const {
+  OnAreExperimentalCookieFeaturesEnabledInternal();
+  return nested_network_delegate_->AreExperimentalCookieFeaturesEnabled();
 }
 
-void LayeredNetworkDelegate::OnFirstPartyOnlyCookieExperimentEnabledInternal()
-    const {
-}
+void LayeredNetworkDelegate::OnAreExperimentalCookieFeaturesEnabledInternal()
+    const {}
 
 bool LayeredNetworkDelegate::
     OnCancelURLRequestWithPolicyViolatingReferrerHeader(