Add the ability to return descedant event listeners.

third_party/WebKit/Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications.",
@@ skipping 3901 matching lines @@
                 "name": "removeXHRBreakpoint",
                 "parameters": [
                     { "name": "url", "type": "string", "description": "Resource URL substring." }
                 ],
                 "description": "Removes breakpoint from XMLHttpRequest."
             },
             {
                 "name": "getEventListeners",
                 "hidden": true,
                 "parameters": [
-                    { "name": "objectId", "$ref": "Runtime.RemoteObjectId", "description": "Identifier of the object to return listeners for." }
+                    { "name": "objectId", "$ref": "Runtime.RemoteObjectId", "description": "Identifier of the object to return listeners for." },
+                    { "name": "descendants", "type": "boolean", "optional": true, "description": "If set, also include event listeners on all descendant nodes." }
                 ],
                 "returns": [
                     { "name": "listeners", "type": "array", "items": { "$ref": "EventListener" }, "description": "Array of relevant listeners." }
                 ],
                 "description": "Returns event listeners of the given object."
             }
         ]
     },
     {
         "domain": "Profiler",
@@ skipping 1235 matching lines @@
                 "parameters": [
                     { "name": "origin", "type": "string", "description": "Security origin." },
                     { "name": "storageTypes", "type": "string", "description": "Comma separated origin names." }
                 ],
                 "description": "Clears storage for origin.",
                 "handlers": ["browser"]
             }
         ]
     }]
 }