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 3897 matching lines @@
                 "description": "Sets breakpoint on XMLHttpRequest."
             },
             {
                 "name": "removeXHRBreakpoint",
                 "parameters": [
                     { "name": "url", "type": "string", "description": "Resource URL substring." }
                 ],
                 "description": "Removes breakpoint from XMLHttpRequest."
             },
             {
                 "name": "getEventListeners",

[caseq, 2016/05/20 01:00:23]

I guess you also want to update
LayoutTests/inspector-protocol/debugger/domdebugger-getEventListeners.html when
you touch this.
Also, should we expose this in UI?

[dtapuska, 2016/05/26 20:37:44]

That was the goal to expose it. But it is kind of unclear what the UX would look
like. It is kind of weird the event listeners get associated with the object you
queried; because they could be low in the tree. I did think perhaps we want to
return the objectId or something like that with the response of the event
listeners indicating the target. But for what it is worth it does work well with
just asking for the listeners on a node and they are associated with that
element.

                 "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": "True if should return all the event listeners in descendants including this node." }

[caseq, 2016/05/20 00:47:24]

nit: "If set, also include event listeners on all descendant nodes"

[dtapuska, 2016/05/26 20:37:44]

Done.

                 ],
                 "returns": [
                     { "name": "listeners", "type": "array", "items": { "$ref": "EventListener" }, "description": "Array of relevant listeners." }
                 ],
                 "description": "Returns event listeners of the given object."
             }
         ]
     },
     {
         "domain": "Profiler",
@@ skipping 1225 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"]
             }
         ]
     }]
 }