Dispatch a new event chrome.contextMenus.onClicked.

chrome/common/extensions/api/context_menus.json

Index: chrome/common/extensions/api/context_menus.json
diff --git a/chrome/common/extensions/api/context_menus.json b/chrome/common/extensions/api/context_menus.json
index c0aae39393573e1cc935b62648a7adba1d7fa133..2fe7f076d4c14cb1526febeb0c6e8a70c2d04290 100644
--- a/chrome/common/extensions/api/context_menus.json
+++ b/chrome/common/extensions/api/context_menus.json
@@ -57,7 +57,7 @@
             "description": "The text for the context selection, if any."
           },
           "editable": {
-            "type": "string",
+            "type": "boolean",
             "description": "A flag indicating whether the element is editable (text input, textarea, etc.)."
           }
         }
@@ -114,7 +114,7 @@
               "onclick": {
                 "type": "function",
                 "optional": true,
-                "description": "A function that will be called back when the menu item is clicked.",
+                "description": "A function that will be called back when the menu item is clicked. Event pages cannot use this; instead, they should register a listener for chrome.contextMenus.onClicked.",
                 "parameters": [
                   {
                     "name": "info",
@@ -277,6 +277,25 @@
           }
         ]
       }
+    ],
+    "events": [
+      {
+        "name": "onClicked",
+        "type": "function",
+        "description": "Fired when a context menu item is clicked.",
+        "parameters": [
+          {
+            "name": "info",
+            "$ref": "OnClickData",
+            "description": "Information about the item clicked and the context where the click happened."
+          },
+          {
+            "name": "tab",
+            "$ref": "tabs.Tab",
+            "description": "The details of the tab where the click took place."
+          }
+        ]
+      }
     ]
   }
 ]