Implement chrome.systemPrivate.getIncognitoModeAvailability extension API function

chrome/common/extensions/api/extension_api.json

Index: chrome/common/extensions/api/extension_api.json
diff --git a/chrome/common/extensions/api/extension_api.json b/chrome/common/extensions/api/extension_api.json
index 6c583344d6baabdaead4db818ccb82eab0037067..e2b1d83b5838e856adc7ed536ba3c9c91b11ad96 100644
--- a/chrome/common/extensions/api/extension_api.json
+++ b/chrome/common/extensions/api/extension_api.json
@@ -9149,5 +9149,18 @@
         ]
       }
     ]
+  },
+  {
+    "namespace": "systemPrivate",
+    "nodoc": true,
+    "types": [],
+    "functions": [],
+    "properties": {
+      "incognitoModeAvailability": {
+        "$ref": "ChromeSetting",
+        "value": ["incognitoModeAvailability", {"type": "string", "enum": ["enabled", "disabled", "forced"]}],
+        "description": "Read-only property that exposes whether the incognito mode is available to windows. One of 'enabled', 'disabled' (user cannot browse pages in Incognito mode), 'forced' (all pages/sessions are forced into Incognito mode)."
+      }
+    }
   }
 ]