Bug 1335743 - Add modifiers field to OnClickData schema r=aswan

MozReview-Commit-ID: E5T4K5iuM6m

--HG--
extra : rebase_source : f4e79dd18122b9a7a3af6a2850e36f801a9a1c96

browser/components/extensions/schemas/context_menus.json

@@ -103,6 +103,14 @@
             "type": "boolean",
             "optional": true,
             "description": "A flag indicating the state of a checkbox or radio item after it is clicked."
+          },
+          "modifiers": {
+            "type": "array",
+            "items": {
+              "type": "string",
+              "enum": ["Shift", "Alt", "Command", "Ctrl", "MacCtrl"]
+            },
+            "description": "An array of keyboard modifiers that were held while the menu item was clicked."
           }
         }
       }