Implement onEvent callback framework for UDP

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "experimental.accessibility",
     "nodoc": true,
     "types": [
       {
         "id": "AccessibilityObject",
         "type": "object",
         "description": "Parent class for accessibility information about an object.",
         "properties": {
@@ skipping 9022 matching lines @@
     "namespace": "experimental.socket",
     "nodoc": true,
     "types": [
       {
         "id": "SocketEvent",
         "type": "object",
         "description": "A socket event.",
         "properties": {
           "type": {
             "type": "string",
-            "enum": ["data", "error"],
-            "description": "A 'data' event represents data received on the socket. An 'error' event represents an error."
+            "enum": ["writeComplete"],
+            "description": "A writeComplete event reports the result of a write that blocked."
           },
-          "byteCount": {
+          "resultCode": {
             "type": "integer",
-            "optional": true,
-            "description": "The number of bytes received in a 'data' event."
-          },
-          "bytes": {
-            "type": "blob",
-            "optional": true,
-            "description": "The data received."
-          },
-          "errorCode": {
-            "type": "integer",
-            "description": "The error code, if the event type is 'error'.",
+            "description": "The result code, if the event type is writeComplete.",
             "optional": true
           },
-          "errorMessage": {
-            "type": "string",
-            "description": "The error description, if the event type is 'error'.",
+          "isFinalEvent": {
+            "type": "boolean",
+            "description": "Whether this is the final event that this socket will send.",
+            "nodoc": true
+          },
+          "srcId": {
+            "type": "number",
+            "description": "An ID unique to the calling function's context so that events can get routed back to the correct callback.",
+            "nodoc": true,
             "optional": true
           }
         }
       }
     ],
     "functions": [
       {
         "name": "create",
         "type": "function",
         "description": "Creates a socket of the specified type.",
@@ skipping 136 matching lines @@
                   "bytesWritten": {
                     "type": "integer",
                     "description": "The number of bytes sent, or a negative error code."
                   }
                 }
               }
             ]
           }
         ]
       }
+    ],
+    "events": [
+      {
+        "name": "onEvent",
+        "type": "function",
+        "nodoc": true,
+        "parameters": [
+          {
+            "name": "event",
+            "$ref": "SocketEvent",
+            "description": "The event indicating socket status."
+          }
+        ],
+        "description": "Used to pass events back to the function that called create()."
+      }
     ]
   },
   {
     "namespace": "systemPrivate",
     "nodoc": true,
     "types": [],
     "functions": [
       {
         "name": "getIncognitoModeAvailability",
         "type": "function",
@@ skipping 10 matching lines @@
                 "enum": ["enabled", "disabled", "forced"],
                 "description": "Exposes whether the incognito mode is available to windows. One of 'enabled', 'disabled' (user cannot browse pages in Incognito mode), 'forced' (all pages/sessions are forced into Incognito mode)."
               }
             ]
           }
         ]
       }
     ]
   }
 ]