Remove extension process side of chrome.devtools API, it's obsolete.

chrome/common/extensions/api/devtools.json

Index: chrome/common/extensions/api/devtools.json
diff --git a/chrome/common/extensions/api/devtools.json b/chrome/common/extensions/api/devtools.json
deleted file mode 100644
index 4a6d9df965b52f2d8da679a3220aa21f08e83312..0000000000000000000000000000000000000000
--- a/chrome/common/extensions/api/devtools.json
+++ /dev/null
@@ -1,30 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-[
-  {
-    "namespace": "devtools",
-    "nodoc": "true",
-    "types": [],
-    "functions": [
-      {
-        "name": "getTabEvents",
-        "type": "function",
-        "description": "Experimental support for timeline API",
-        "nodoc": "true",
-        "parameters": [
-          {
-            "name": "tab_id",
-            "type": "integer"
-          }
-        ],
-        "returns": {
-          "type": "object",
-          "additionalProperties": { "type": "any" },
-          "description": "DevTools tab events object"
-        }
-      }
-    ]
-  }
-]