Fix loading success.html at the end of chrome://chrome-signin flow

extensions/common/api/_manifest_features.json

Index: extensions/common/api/_manifest_features.json
diff --git a/extensions/common/api/_manifest_features.json b/extensions/common/api/_manifest_features.json
index 8b10f3df75b4a0533bd4a39c1f63de0dd8789c3b..cf59a0b1568595ef5d69bb1febf93166ac2f05bf 100644
--- a/extensions/common/api/_manifest_features.json
+++ b/extensions/common/api/_manifest_features.json
@@ -332,9 +332,20 @@
       "location": "component"
     }
   ],
-  "webview": {
-    "channel": "stable",
-    "extension_types": ["platform_app"],
-    "min_manifest_version": 2
-  }
+  "webview": [
+    {
+      "channel": "stable",
+      "extension_types": [ "platform_app" ],
+      "min_manifest_version": 2
+    },
+    {
+      "channel": "stable",
+      "extension_types": [ "extension" ],
+      "whitelist": [
+        // Chrome sign-in extension needs to load web accessibile resources
+        // at the end of the sign-in flow.
+        "D519188F86D9ACCEE0412007B227D9936EB9676B"  // http://crbug.com/709117
+      ]
+    }
+  ]
 }