[SystemInfo API] Move Storage API out of experimental namespace and rename to the "system" namespace

chrome/common/extensions/api/_permission_features.json

 // Copyright (c) 2012 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.
 
 // See c/c/e/features/* to understand this file, in particular feature.h,
 // simple_feature.h, and base_feature_provider.h.
 
 {
   "activeTab": {
     "channel": "stable",
@@ skipping 512 matching lines @@
   "storage": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app", "platform_app"],
     "min_manifest_version": 2
   },
   "system.cpu": {
     "channel": "dev",
     "extension_types": [
       "extension", "packaged_app", "hosted_app", "platform_app"
     ],
     "whitelist": [""]

[Haojian Wu, 2013/07/29 07:26:36]

Should we remove the "whitelist" restriction of system.cpu and system.memory
here? 

Now extensions/web apps using these APIs should be included in whitelist(run
through ./chrome.exe --whitelisted-extension-id=XX), otherwise these APIs are
not available. 

[not at google - send to devlin, 2013/07/29 14:51:52]

Why do we bother supporting this...?

[Haojian Wu, 2013/07/30 02:10:47]

I just keep the cpu/memory API unchanged here.
see
(https://codereview.chromium.org/16256023/diff/24001/chrome/common/extensions/...,
and
https://codereview.chromium.org/15817008/diff/27001/chrome/common/extensions/...)
these two patches add "whitelist" restrictions. 

   },
   "system.memory": {
     "channel": "dev",
     "extension_types": [
       "extension", "packaged_app", "hosted_app", "platform_app"
     ],
     "whitelist": [""]
   },
+  "system.storage": {
+    "channel": "stable",
+    "extension_types": [
+      "extension", "packaged_app", "platform_app"
+    ]
+  },
   "system.display": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app", "platform_app"]
   },
   "systemPrivate": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"],
     "location": "component"
   },
   "tabs": {
@@ skipping 86 matching lines @@
   },
   "webRequestBlocking": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   },
   "webview": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   }
 }