First-Party Cookies: Wire it up as an experimental web platform feature

chrome/browser/net/chrome_network_delegate.h

Index: chrome/browser/net/chrome_network_delegate.h
diff --git a/chrome/browser/net/chrome_network_delegate.h b/chrome/browser/net/chrome_network_delegate.h
index 4635e57422fbc183b935b81887dafb9e515e2fed..82126638d901785225692f79979924e444c3d9fd 100644
--- a/chrome/browser/net/chrome_network_delegate.h
+++ b/chrome/browser/net/chrome_network_delegate.h
@@ -128,6 +128,10 @@ class ChromeNetworkDelegate : public net::NetworkDelegateImpl {
   // Adds the Client Hints header to HTTP requests.
   void SetEnableClientHints();
 
+  // Notes that "experimental web platform features" are enabled, which in turn
+  // can enable web-facing //net experiments.
+  void SetExperimentalWebPlatformFeaturesEnabled();
+
   // Causes |OnCanThrottleRequest| to always return false, for all
   // instances of this object.
   static void NeverThrottleRequests();
@@ -188,6 +192,7 @@ class ChromeNetworkDelegate : public net::NetworkDelegateImpl {
   bool OnCanEnablePrivacyMode(
       const GURL& url,
       const GURL& first_party_for_cookies) const override;
+  bool OnFirstPartyCookieExperimentEnabled() const override;
   bool OnCancelURLRequestWithPolicyViolatingReferrerHeader(
       const net::URLRequest& request,
       const GURL& target_url,
@@ -230,6 +235,7 @@ class ChromeNetworkDelegate : public net::NetworkDelegateImpl {
   static bool g_never_throttle_requests_;
 
   scoped_ptr<ClientHints> client_hints_;
+  bool experimental_web_platform_features_enabled_;
 
   bool first_request_;