Enable _api_features.json to block APIs from service worker contexts.

extensions/common/features/feature.h

Index: extensions/common/features/feature.h
diff --git a/extensions/common/features/feature.h b/extensions/common/features/feature.h
index 67201f07fddb6e3abf55566a97a5445c5c9ea858..8afc15d1dce7d7769e90bb340eb6ecf19534a5c6 100644
--- a/extensions/common/features/feature.h
+++ b/extensions/common/features/feature.h
@@ -120,6 +120,9 @@ class Feature {
   // Tests whether this is an internal API or not.
   virtual bool IsInternal() const = 0;
 
+  // Returns True for features excluded from service worker backed contexts.
+  virtual bool IsBlockedInServiceWorker() const = 0;
+
   // Returns true if the feature is available to be parsed into a new extension
   // manifest.
   Availability IsAvailableToManifest(const std::string& extension_id,