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 ac99dffe27615b689144e66c6ae2f1e9139a2888..2776f643f3cc63cac9379b607a0b20a7855ebf21 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(

[pfeldman, 2016/08/12 18:49:23]

If I did not specify the experimental-web-platform command line flag and there
is origin trial policy and it has foreign fetch disabled, we should return.

So missing origin_trial_policy allows foreign fetch?

[Marijn Kruisselbrink, 2016/08/12 19:15:40]

Ah, good point. I was trying to mimic what TrialTokenValidator does, but that
indeed disables all origin trials if no origin_trial_policy is present. To clean
this all up a bit I moved this whole check (after fixing it) to a separate
IsForeignFetchEnabled method, and call that both from here and
StoragePartitionImplMap.

+          switches::kEnableExperimentalWebPlatformFeatures) &&
+      origin_trial_policy &&
+      origin_trial_policy->IsFeatureDisabled("ForeignFetch")) {
+    return;
+  }
+
   if (!context_wrapper)
     return;