Support output for Chrome's native find in ChromeVox.

chrome/browser/resources/chromeos/chromevox/cvox2/background/find_handler.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.
+/**
+ * @fileoverview Handles output for Chrome's built-in find.
+ */
+goog.provide('FindHandler');
+
+goog.require('Output');
+
+/**
+ * Responds to mode changes.
+ * @param {ChromeVoxMode} newMode
+ * @param {?ChromeVoxMode} oldMode Can be null at startup when no range was
+ *  previously set.
+ */
+FindHandler.onModeChanged = function(newMode, oldMode) {
+  if (newMode == ChromeVoxMode.FORCE_NEXT)
+    FindHandler.init_();
+  else
+    FindHandler.uninit_();
+};
+
+/**
+ * Initializes this module.
+ * @private
+ */
+FindHandler.init_ = function() {
+  chrome.automation.addTreeChangeObserver(
+      'textMarkerChanges', FindHandler.onTextMatch_);
+};
+
+/**
+ * Uninitializes this module.
+ * @private
+ */
+FindHandler.uninit_ = function() {
+  chrome.automation.removeTreeChangeObserver(FindHandler.onTextMatch_);
+};
+
+/**
+ * @param {Object} evt
+ * @private
+ */
+FindHandler.onTextMatch_ = function(evt) {
+  if (!evt.target.markerTypes.some(function(markerType) {
+          return markerType & 4 /* Text match */;
+      }))
+    return;
+
+  var range = cursors.Range.fromNode(evt.target);
+  ChromeVoxState.instance.setCurrentRange(range);
+  new Output()
+      .withRichSpeechAndBraille(range, null, Output.EventType.NAVIGATE)
+      .go();
+};