Fix small error in relative bounds calc for Chrome OS only.

chrome/test/data/extensions/api_test/automation/tests/tabs/location2.js

+// Copyright 2016 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.
+
+var allTests = [
+  // This is a regression test for a particular layout where the
+  // automation API was returning the wrong location for an element.
+  // See ../../sites/location2.html for the layout.
+  function testLocation2() {
+    var textbox = rootNode.find({ role: RoleType.textField });
+    assertEq(0, textbox.location.left - rootNode.location.left);
+    assertEq(100, textbox.location.top - rootNode.location.top);
+    chrome.test.succeed();
+  }
+];
+
+setUpAndRunTests(allTests, 'location2.html');