Enable the chrome.declarativeContent API on the stable channel.

BUG=308651

Review URL: https://codereview.chromium.org/102433011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243414 0039d316-1c4b-4281-b951-d872f2087c98

chrome/common/extensions/api/_permission_features.json

@@ -270,7 +270,7 @@
     "extension_types": ["extension", "legacy_packaged_app"]
   },
   "declarativeContent": {
-    "channel": "dev",
+    "channel": "stable",
     "extension_types": ["extension"]
   },
   "declarativeWebRequest": [