Begin to enable extension APIs in Extension Service Worker.

extensions/common/features/simple_feature_unittest.cc

Index: extensions/common/features/simple_feature_unittest.cc
diff --git a/extensions/common/features/simple_feature_unittest.cc b/extensions/common/features/simple_feature_unittest.cc
index e74dc32fb14560c20bcbb06949fb43dd7ca1f057..f2d2d2d663c79b17df47e06e70c1b3e543abd750 100644
--- a/extensions/common/features/simple_feature_unittest.cc
+++ b/extensions/common/features/simple_feature_unittest.cc
@@ -561,10 +561,11 @@ TEST_F(SimpleFeatureTest, ParseContexts) {
   contexts->Append(new base::StringValue("web_page"));
   contexts->Append(new base::StringValue("blessed_web_page"));
   contexts->Append(new base::StringValue("webui"));
+  contexts->Append(new base::StringValue("extension_service_worker"));
   value->Set("contexts", contexts);
   std::unique_ptr<SimpleFeature> feature(new SimpleFeature());
   feature->Parse(value.get());
-  EXPECT_EQ(6u, feature->contexts()->size());
+  EXPECT_EQ(7u, feature->contexts()->size());
   EXPECT_TRUE(
       STLCount(*(feature->contexts()), Feature::BLESSED_EXTENSION_CONTEXT));
   EXPECT_TRUE(