[Extensions] Clean up renderer channel-related code

extensions/common/features/feature_util.h

Index: extensions/common/features/feature_util.h
diff --git a/extensions/common/features/feature_util.h b/extensions/common/features/feature_util.h
index f8d60061e6205112be0cfeb7e4dcd33427ea8a35..342cc666a1987217cf31342e18310d4910ef8070 100644
--- a/extensions/common/features/feature_util.h
+++ b/extensions/common/features/feature_util.h
@@ -28,4 +28,15 @@
     LOG(FATAL) << message_copy;                                                \
   }
 
+namespace extensions {
+namespace feature_util {
+
+// Returns true if service workers are enabled for extension schemes.
+// TODO(lazyboy): Remove this function once extension Service Workers
+// are enabled by default for a while.
+bool ExtensionServiceWorkersEnabled();
+
+}  // namespace feature_util
+}  // namespace extensions
+
 #endif  // EXTENSIONS_COMMON_FEATURES_FEATURE_UTIL_H_