[Extensions] Use compiled feature files

extensions/test/BUILD.gn

+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//tools/json_schema_compiler/json_features.gni")
+
+json_features("test_api_features") {
+  feature_class = "APIFeature"
+  provider_class = "TestAPIFeatureProvider"
+  sources = [
+    "../common/api/_api_features.json",
+  ]
+}
+
+json_features("test_permission_features") {
+  feature_class = "PermissionFeature"
+  provider_class = "TestPermissionFeatureProvider"
+  sources = [
+    "../common/api/_permission_features.json",
+  ]
+}
+
+json_features("test_manifest_features") {
+  feature_class = "ManifestFeature"
+  provider_class = "TestManifestFeatureProvider"
+  sources = [
+    "../common/api/_manifest_features.json",
+  ]
+}
+
+json_features("test_behavior_features") {
+  feature_class = "BehaviorFeature"
+  provider_class = "TestBehaviorFeatureProvider"
+  sources = [
+    "../common/api/_behavior_features.json",
+  ]
+}
+
+group("extensions_features") {
+  public_deps = [
+    ":test_api_features",
+    ":test_behavior_features",
+    ":test_manifest_features",
+    ":test_permission_features",
+  ]
+}