Begin to enable extension APIs in Extension Service Worker.

extensions/common/features/simple_feature.cc

Index: extensions/common/features/simple_feature.cc
diff --git a/extensions/common/features/simple_feature.cc b/extensions/common/features/simple_feature.cc
index 68c8dfa175f8100ed6cca8291788422bbf58395d..686fdebc42ce8fd415f43ec4f216eb6b22c786da 100644
--- a/extensions/common/features/simple_feature.cc
+++ b/extensions/common/features/simple_feature.cc
@@ -263,6 +263,7 @@ struct SimpleFeature::Mappings {
     contexts["web_page"] = Feature::WEB_PAGE_CONTEXT;
     contexts["blessed_web_page"] = Feature::BLESSED_WEB_PAGE_CONTEXT;
     contexts["webui"] = Feature::WEBUI_CONTEXT;
+    contexts["extension_service_worker"] = Feature::SERVICE_WORKER_CONTEXT;

[Devlin, 2016/04/13 19:46:31]

We should have this behind a flag (or just an internal bool we can flip for
testing/experimentation) until we get some of the TODOs ironed out.

[lazyboy, 2016/04/14 02:07:53]

I've added a bool in feature_util, used that to guard some key code: the message
filter and the ServiceWorkerData and worker request sender code. However this
very line is not guarded as I need to guard _api_features.json too.

Since we need to turn this on in tests, and we need to sync the bool in
renderer/ process, this also involves IPC :( Let me know if you have a better
suggestion.

[Devlin, 2016/04/14 22:34:52]

See suggestion in ipc messages.

 
     locations["component"] = SimpleFeature::COMPONENT_LOCATION;
     locations["external_component"] =
@@ -439,6 +440,10 @@ Feature::Availability SimpleFeature::IsAvailableToContext(
       return result;
   }
 
+  // TODO(lazyboy): This isn't quite right for Extension Service Worker
+  // extension API calls, since there's no guarantee that the extension is
+  // "active" in current renderer process when the API permission check is
+  // done.
   if (!contexts_.empty() && !ContainsValue(contexts_, context))
     return CreateAvailability(INVALID_CONTEXT, context);