Enable ServiceWorkerNavigationPreload by default for Origin-Trial.

content/public/common/content_features.cc

Index: content/public/common/content_features.cc
diff --git a/content/public/common/content_features.cc b/content/public/common/content_features.cc
index 338a7745240a1b4a6e04a8fd0e4b57109a280e8b..277ce98d27dd6e0212e9844ff14eac12d6932847 100644
--- a/content/public/common/content_features.cc
+++ b/content/public/common/content_features.cc
@@ -189,10 +189,12 @@ const base::Feature kScrollAnchoring{"ScrollAnchoring",
                                      base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Navigation preload feature of service workers.
-// TODO(horo): Revise link when this lands in the spec:
-// https://github.com/w3c/ServiceWorker/pull/983/files
+// We enable this base::Feature by default for Origin-Trial. But in
+// runtime_features.cc, we enable the blink::WebRuntimeFeatures only when it is
+// enabled by "--enable-features" command line flag. See the comments in
+// runtime_features.cc and service_worker_version.h for the details.

[kinuko, 2017/01/16 05:07:10]

nit: avoid using 'we' in general, e.g. 'Enables this base::Feature by default
for Origin-Trial, but enables the corresponding blink::WebRuntimeFeatures only
when '--enable-features' command line flag is given.  See the...'

[horo, 2017/01/16 05:30:36]

Done.

 const base::Feature kServiceWorkerNavigationPreload{
-    "ServiceWorkerNavigationPreload", base::FEATURE_DISABLED_BY_DEFAULT};
+    "ServiceWorkerNavigationPreload", base::FEATURE_ENABLED_BY_DEFAULT};
 
 // http://tc39.github.io/ecmascript_sharedmem/shmem.html
 const base::Feature kSharedArrayBuffer{"SharedArrayBuffer",