Make Foreign Fetch an origin trial.

content/browser/service_worker/foreign_fetch_request_handler.cc

Index: content/browser/service_worker/foreign_fetch_request_handler.cc
diff --git a/content/browser/service_worker/foreign_fetch_request_handler.cc b/content/browser/service_worker/foreign_fetch_request_handler.cc
index 9b213107576e47752ea75ff9f498be888be9d1aa..dc8fffde434016b212a065b73b13154387f3673a 100644
--- a/content/browser/service_worker/foreign_fetch_request_handler.cc
+++ b/content/browser/service_worker/foreign_fetch_request_handler.cc
@@ -6,12 +6,16 @@
 
 #include <string>
 
+#include "base/command_line.h"
 #include "base/macros.h"
 #include "content/browser/service_worker/service_worker_context_wrapper.h"
 #include "content/browser/service_worker/service_worker_response_info.h"
 #include "content/browser/service_worker/service_worker_url_request_job.h"
 #include "content/common/resource_request_body_impl.h"
 #include "content/common/service_worker/service_worker_utils.h"
+#include "content/public/common/content_client.h"
+#include "content/public/common/content_switches.h"
+#include "content/public/common/origin_trial_policy.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_interceptor.h"
 #include "storage/browser/blob/blob_storage_context.h"
@@ -60,6 +64,15 @@ void ForeignFetchRequestHandler::InitializeHandler(
     RequestContextFrameType frame_type,
     scoped_refptr<ResourceRequestBodyImpl> body,
     bool initiated_in_secure_context) {
+  OriginTrialPolicy* origin_trial_policy =
+      GetContentClient()->GetOriginTrialPolicy();
+  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableExperimentalWebPlatformFeatures) &&
+      origin_trial_policy &&
+      origin_trial_policy->IsFeatureDisabled("ForeignFetch")) {
+    return;
+  }
+
   if (!context_wrapper)
     return;