Implements extensions devtools API

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "types": [
       {
         "id": "Port",
         "type": "object",
         "description": "An object which allows two way communication with other pages.",
         "properties": {
           "name": {"type": "string"},
@@ skipping 847 matching lines @@
         "description": "",
         "parameters": [
           {"type": "string", "name": "url", "optional": true},
           {"type": "function", "name": "callback", "optional": true, "parameters": []}
         ]
       }
     ],
     "events": []
   },
   {
+    "namespace": "devtools",
+    "types": [
+    ],
+    "functions": [
+      {
+        "name": "getTabEvents",
+        "type": "function",
+        "description": "EXPERIMENTAL support for timeline API",
+        "nodocs": "true",
+        "parameters": [
+          {
+            "name": "tab_id",
+            "type": "integer"
+          }
+        ],
+        "returns": {
+          "type": "object",
+          "description": "DevTools tab events object"
+        }
+      }
+    ]
+  },
+  {
     "namespace": "test",
     "types": [],
     "functions": [
       {
         "name": "fail",
         "type": "function",
         "description": "Notify the browser process that test code running in the extension failed.  This is only used for internal unit testing.",
         "parameters": [
           {"type": "string", "name": "message"}
         ]
       },
       {
         "name": "pass",
         "type": "function",
         "description": "Notify the browser process that test code running in the extension passed.  This is only used for internal unit testing.",
         "parameters": []
       }
     ],
     "events": []
   }
 ]