Move the `privacy` extension API out of experimental.

chrome/common/extensions/docs/samples.json

 {
   "api": {
     "chrome.bookmarks.create": "bookmarks.html#method-create",
     "chrome.bookmarks.export": "bookmarks.html#method-export",
     "chrome.bookmarks.get": "bookmarks.html#method-get",
     "chrome.bookmarks.getChildren": "bookmarks.html#method-getChildren",
     "chrome.bookmarks.getRecent": "bookmarks.html#method-getRecent",
     "chrome.bookmarks.getSubTree": "bookmarks.html#method-getSubTree",
     "chrome.bookmarks.getTree": "bookmarks.html#method-getTree",
     "chrome.bookmarks.import": "bookmarks.html#method-import",
@@ skipping 392 matching lines @@
       "zip_path": "examples\/api\/override\/blank_ntp.zip"
     },
     {
       "api_calls": [
         "chrome.extension.isAllowedIncognitoAccess"
       ],
       "crx_path": null,
       "description": "Sample extension which demonstrates how to access a preference.",
       "features": [
         "browser_action",
-        "experimental",
         "privacy"
       ],
       "icon": null,
       "id": "0bf0930a32829dfb77170535ecb27adc2de3998a",
       "name": "Block\/allow referrer API example extension",
       "packaged_app": false,
       "path": "examples\/api\/preferences\/enableReferrer\/",
       "protocols": [],
-      "search_string": "BLOCK\/ALLOW REFERRER API EXAMPLE EXTENSION SAMPLE EXTENSION WHICH DEMONSTRATES HOW TO ACCESS A PREFERENCE. BROWSER_ACTION EXPERIMENTAL PRIVACY CHROME.EXTENSION.ISALLOWEDINCOGNITOACCESS",
+      "search_string": "BLOCK\/ALLOW REFERRER API EXAMPLE EXTENSION SAMPLE EXTENSION WHICH DEMONSTRATES HOW TO ACCESS A PREFERENCE. BROWSER_ACTION PRIVACY CHROME.EXTENSION.ISALLOWEDINCOGNITOACCESS",
       "source_files": [
         "manifest.json",
         "popup.css",
         "popup.html",
         "popup.js"
       ],
-      "source_hash": "51bbc12404e8998ef817e211806e734f04e138ad",
+      "source_hash": "463b9acbbe50a9c6a62e7cd6546087dc06df1b4f",
       "zip_path": "examples\/api\/preferences\/enableReferrer.zip"
     },
     {
       "api_calls": [
         "chrome.extension.isAllowedIncognitoAccess"
       ],
       "crx_path": null,
       "description": "Sample extension which demonstrates how to access a preference.",
       "features": [
         "browser_action",
-        "experimental",
         "privacy"
       ],
       "icon": null,
       "id": "7da105f28e200d42510aff3591dfa5aeb0b82605",
       "name": "Block\/allow third-party cookies API example extension",
       "packaged_app": false,
       "path": "examples\/api\/preferences\/allowThirdPartyCookies\/",
       "protocols": [],
-      "search_string": "BLOCK\/ALLOW THIRD-PARTY COOKIES API EXAMPLE EXTENSION SAMPLE EXTENSION WHICH DEMONSTRATES HOW TO ACCESS A PREFERENCE. BROWSER_ACTION EXPERIMENTAL PRIVACY CHROME.EXTENSION.ISALLOWEDINCOGNITOACCESS",
+      "search_string": "BLOCK\/ALLOW THIRD-PARTY COOKIES API EXAMPLE EXTENSION SAMPLE EXTENSION WHICH DEMONSTRATES HOW TO ACCESS A PREFERENCE. BROWSER_ACTION PRIVACY CHROME.EXTENSION.ISALLOWEDINCOGNITOACCESS",
       "source_files": [
         "manifest.json",
         "popup.css",
         "popup.html",
         "popup.js"
       ],
-      "source_hash": "10d84072f653cfafc7796d5600d2f076a2398a4f",
+      "source_hash": "b9f3b8723ecc125ddf47f49987bfcd089591e0d2",
       "zip_path": "examples\/api\/preferences\/allowThirdPartyCookies.zip"
     },
     {
       "api_calls": [
         "chrome.experimental.devtools.audits.addCategory",
         "chrome.extension.onRequest",
         "chrome.extension.sendRequest",
         "chrome.tabs.executeScript",
         "chrome.tabs.sendRequest"
       ],
@@ skipping 1994 matching lines @@
         "manifest.json",
         "popup.html",
         "popup.js",
         "sample.css"
       ],
       "source_hash": "8e51dc3a9577065d22ce92f3c838edc5ceaf4e65",
       "zip_path": "examples\/api\/extension\/isAllowedAccess.zip"
     }
   ]
 }