Split feature definitions into extensions and chrome features.

extensions/common/api/_api_features.json

+// Copyright 2014 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.
+
+// This features file defines extension APIs implemented under src/extensions.
+// See extensions/common/features/* to understand this file, in particular
+// feature.h, simple_feature.h, and base_feature_provider.h.
+//
+// Note that specifying "web_page", "blessed_web_page", or "all" as a context
+// type will require manually updating chrome/renderer/resources/dispatcher.cc.
+
+{
+  "dns": {
+    "dependencies": ["permission:dns"],
+    "contexts": ["blessed_extension"]
+  },
+  "socket": {
+    "dependencies": ["permission:socket"],
+    "contexts": ["blessed_extension"]
+  },
+  "sockets.tcp": {
+    "dependencies": ["manifest:sockets"],
+    "contexts": ["blessed_extension"]
+  },
+  "sockets.tcpServer": {
+    "dependencies": ["manifest:sockets"],
+    "contexts": ["blessed_extension"]
+  },
+  "sockets.udp": {
+    "dependencies": ["manifest:sockets"],
+    "contexts": ["blessed_extension"]
+  },
+  "storage": {
+    "dependencies": ["permission:storage"],
+    "contexts": ["blessed_extension", "unblessed_extension", "content_script"]
+  },
+  "test": {
+    "internal": true,
+    "channel": "stable",
+    "extension_types": "all",
+    "contexts": ["blessed_extension", "unblessed_extension", "content_script"]
+  }
+}