Add private system extension API to get system update status

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 30d2d0c81de47fd8c5c5917ef4232fa099086bff..92269cadc560b6bb7d68dce9a0488b5b764805ad 100644
--- a/chrome/common/extensions/api/extension_api.json
+++ b/chrome/common/extensions/api/extension_api.json
@@ -9110,7 +9110,24 @@
   {
     "namespace": "systemPrivate",
     "nodoc": true,
-    "types": [],
+    "types": [
+      {
+        "id": "UpdateStatus",
+        "type": "object",
+        "description": "Information about the system update.",
+        "properties": {
+          "state": {
+            "type": "string",
+            "enum": ["NotAvailable", "Updating", "NeedRestart"],
+            "description": "State of system update.  NotAvailable when there is no available update or the update system is in error state, Updating when a system update is in progress, NeedRestart when a system update is finished and restart is needed."
+          },
+          "download_progress": {
+            "type": "number",
+            "description": "Value between 0 and 1 describing the progress of system update download.  This value will be set to 0 when |state| is NotAvailable, 1 when NeedRestart."
+          }
+        }
+      }
+    ],
     "functions": [
       {
         "name": "getIncognitoModeAvailability",
@@ -9131,6 +9148,24 @@
             ]
           }
         ]
+      },
+      {
+        "name": "getUpdateStatus",
+        "type": "function",
+        "description": "Gets information about the system update.",
+        "parameters": [
+          {
+            "type": "function",
+            "name": "callback",
+            "parameters": [
+              {
+                "$ref": "UpdateStatus",
+                "name": "status",
+                "description": "Details of the system update"
+              }
+            ]
+          }
+        ]
       }
     ]
   }