Fix computation of Automation API location offsets in WebViews.

chrome/test/data/extensions/api_test/automation/tests/webview/location_in_webview.js

+// Copyright 2017 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 assertTrue = chrome.test.assertTrue;
+
+var EventType = chrome.automation.EventType;
+
+var allTests = [
+  function testLocationInWebView() {
+    rootNode.addEventListener(EventType.LOAD_COMPLETE, function() {
+      var outerButton = rootNode.find({ attributes: { name: 'Outer' } });
+      var innerButton = rootNode.find({ attributes: { name: 'Inner' } });
+      if (outerButton && innerButton) {
+        var outerRect = outerButton.location;
+        var innerRect = innerButton.location;
+
+        // The outer button should be at (50, 150). Allow one pixel off
+        // for rounding errors.
+        assertTrue(Math.abs(outerRect.left - 50) <= 1);
+        assertTrue(Math.abs(outerRect.top - 150) <= 1);
+
+        // The inner button should be exactly 100 x 200 pixels offset from
+        // the outer button.
+        assertTrue(Math.abs(innerRect.left - outerRect.left - 100) <= 1);
+        assertTrue(Math.abs(innerRect.top - outerRect.top - 200) <= 1);
+        chrome.test.succeed();
+      }
+    }, false);
+
+    chrome.app.window.create('webview_frame.html', {
+      'innerBounds': {
+        'left': 50,
+        'top': 150,
+        'width': 400,
+        'height': 400
+      }
+    });
+  }
+];
+
+chrome.automation.getDesktop(function(rootNodeArg) {
+  window.rootNode = rootNodeArg;
+  chrome.test.runTests(allTests);
+});