Get rid of deprecated live regions code from ChromeVox

BUG=none

Review URL: https://codereview.chromium.org/611473004

Cr-Commit-Position: refs/heads/master@{#297526}

chrome/browser/resources/chromeos/chromevox/chromevox/injected/event_watcher.js

@@ -25,7 +25,6 @@ goog.require('cvox.DomUtil');
 goog.require('cvox.Focuser');
 goog.require('cvox.History');
 goog.require('cvox.LiveRegions');
-goog.require('cvox.LiveRegionsDeprecated');
 goog.require('cvox.Memoize');
 goog.require('cvox.NavigationSpeaker');
 goog.require('cvox.PlatformFilter');  // TODO: Find a better place for this.
@@ -59,26 +58,6 @@ cvox.ChromeVoxEventWatcher.MAX_WAIT_TIME_MS_ = 50;
  */
 cvox.ChromeVoxEventWatcher.WAIT_TIME_MS_ = 10;
 
-/**
- * Amount of time in ms to wait before considering a subtree modified event to
- * be the start of a new burst of subtree modified events.
- * @const
- * @type {number}
- * @private
- */
-cvox.ChromeVoxEventWatcher.SUBTREE_MODIFIED_BURST_DURATION_ = 1000;
-
-
-/**
- * Number of subtree modified events that are part of the same burst to process
- * before we give up on processing any more events from that burst.
- * @const
- * @type {number}
- * @private
- */
-cvox.ChromeVoxEventWatcher.SUBTREE_MODIFIED_BURST_COUNT_LIMIT_ = 3;
-
-
 /**
  * Maximum number of live regions that we will attempt to process.
  * @const
@@ -246,20 +225,6 @@ cvox.ChromeVoxEventWatcher.secondPassThroughKeyUp_ = false;
   cvox.ChromeVoxEventWatcher.textMutationObserver_ = null;
 
   cvox.ChromeVoxEventWatcher.addEventListeners_(doc);
-
-  /**
-   * The time when the last burst of subtree modified events started
-   * @type {number}
-   * @private
-   */
-  cvox.ChromeVoxEventWatcher.lastSubtreeModifiedEventBurstTime_ = 0;
-
-  /**
-   * The number of subtree modified events in the current burst.
-   * @type {number}
-   * @private
-   */
-  cvox.ChromeVoxEventWatcher.subtreeModifiedEventsCount_ = 0;
 };
 
 
@@ -414,31 +379,26 @@ cvox.ChromeVoxEventWatcher.addEventListeners_ = function(doc) {
   cvox.ChromeVoxEventWatcher.addEventListener_(doc,
       'click', cvox.ChromeVoxEventWatcher.mouseClickEventWatcher, true);
 
-  if (typeof(window.WebKitMutationObserver) != 'undefined') {
-    cvox.ChromeVoxEventWatcher.mutationObserver_ =
-        new window.WebKitMutationObserver(
-            cvox.ChromeVoxEventWatcher.mutationHandler);
-    var observerTarget = null;
-    if (doc.documentElement) {
-      observerTarget = doc.documentElement;
-    } else if (doc.document && doc.document.documentElement) {
-      observerTarget = doc.document.documentElement;
-    }
-    if (observerTarget) {
-      cvox.ChromeVoxEventWatcher.mutationObserver_.observe(
-          observerTarget,
-          /** @type {!MutationObserverInit} */ ({
-            childList: true,
-            attributes: true,
-            characterData: true,
-            subtree: true,
-            attributeOldValue: true,
-            characterDataOldValue: true
-          }));
-    }
-  } else {
-    cvox.ChromeVoxEventWatcher.addEventListener_(doc, 'DOMSubtreeModified',
-        cvox.ChromeVoxEventWatcher.subtreeModifiedEventWatcher, true);
+  cvox.ChromeVoxEventWatcher.mutationObserver_ =
+      new window.WebKitMutationObserver(
+          cvox.ChromeVoxEventWatcher.mutationHandler);
+  var observerTarget = null;
+  if (doc.documentElement) {
+    observerTarget = doc.documentElement;
+  } else if (doc.document && doc.document.documentElement) {
+    observerTarget = doc.document.documentElement;
+  }
+  if (observerTarget) {
+    cvox.ChromeVoxEventWatcher.mutationObserver_.observe(
+        observerTarget,
+        /** @type {!MutationObserverInit} */ ({
+          childList: true,
+          attributes: true,
+          characterData: true,
+          subtree: true,
+          attributeOldValue: true,
+          characterDataOldValue: true
+        }));
   }
 };
 
@@ -951,20 +911,6 @@ cvox.ChromeVoxEventWatcher.selectEventWatcher = function(evt) {
   return true;
 };
 
-/**
- * Watches for DOM subtree modified events.
- *
- * @param {Event} evt The event to add to the queue.
- * @return {boolean} True if the default action should be performed.
- */
-cvox.ChromeVoxEventWatcher.subtreeModifiedEventWatcher = function(evt) {
-  if (!evt || !evt.target) {
-    return true;
-  }
-  cvox.ChromeVoxEventWatcher.addEvent(evt);
-  return true;
-};
-
 /**
  * Listens for WebKit visibility change events.
  */
@@ -1000,47 +946,6 @@ cvox.ChromeVoxEventWatcher.speakLiveRegion_ = function(
   descSpeaker.speakDescriptionArray(messages, queueMode, null);
 };
 
-/**
- * Handles DOM subtree modified events passed to it from the events queue.
- * If the change involves an ARIA live region, then speak it.
- *
- * @param {Event} evt The event to handle.
- */
-cvox.ChromeVoxEventWatcher.subtreeModifiedHandler = function(evt) {
-  // Subtree modified events can happen in bursts. If several events happen at
-  // the same time, trying to process all of them will slow ChromeVox to
-  // a crawl and make the page itself unresponsive (ie, Google+).
-  // Before processing subtree modified events, make sure that it is not part of
-  // a large burst of events.
-  // TODO (clchen): Revisit this after the DOM mutation events are
-  // available in Chrome.
-  var currentTime = new Date().getTime();
-
-  if ((cvox.ChromeVoxEventWatcher.lastSubtreeModifiedEventBurstTime_ +
-      cvox.ChromeVoxEventWatcher.SUBTREE_MODIFIED_BURST_DURATION_) >
-      currentTime) {
-    cvox.ChromeVoxEventWatcher.subtreeModifiedEventsCount_++;
-    if (cvox.ChromeVoxEventWatcher.subtreeModifiedEventsCount_ >
-        cvox.ChromeVoxEventWatcher.SUBTREE_MODIFIED_BURST_COUNT_LIMIT_) {
-      return;
-    }
-  } else {
-    cvox.ChromeVoxEventWatcher.lastSubtreeModifiedEventBurstTime_ = currentTime;
-    cvox.ChromeVoxEventWatcher.subtreeModifiedEventsCount_ = 1;
-  }
-
-  if (!evt || !evt.target) {
-    return;
-  }
-  var target = /** @type {Element} */ (evt.target);
-  var regions = cvox.AriaUtil.getLiveRegions(target);
-  for (var i = 0; (i < regions.length) &&
-      (i < cvox.ChromeVoxEventWatcher.MAX_LIVE_REGIONS_); i++) {
-    cvox.LiveRegionsDeprecated.updateLiveRegion(
-        regions[i], cvox.ChromeVoxEventWatcher.queueMode_(), false);
-  }
-};
-
 /**
  * Sets up the text handler.
  * @return {boolean} True if an editable text control has focus.
@@ -1443,8 +1348,7 @@ cvox.ChromeVoxEventWatcher.doProcessQueue_ = function() {
   cvox.ChromeVoxEventWatcher.events_ = [];
   for (i = 0; evt = events[i]; i++) {
     var prevEvt = events[i - 1] || {};
-    if ((i >= lastFocusIndex || evt.type == 'LiveRegion' ||
-        evt.type == 'DOMSubtreeModified') &&
+    if ((i >= lastFocusIndex || evt.type == 'LiveRegion') &&
         (prevEvt.type != 'focus' || evt.type != 'change')) {
       cvox.ChromeVoxEventWatcher.events_.push(evt);
     }
@@ -1454,9 +1358,6 @@ cvox.ChromeVoxEventWatcher.doProcessQueue_ = function() {
     if (b.type != 'LiveRegion' && a.type == 'LiveRegion') {
       return 1;
     }
-    if (b.type != 'DOMSubtreeModified' && a.type == 'DOMSubtreeModified') {
-      return 1;
-    }
     return -1;
   });
 
@@ -1534,9 +1435,6 @@ cvox.ChromeVoxEventWatcher.handleEvent_ = function(evt) {
       cvox.ChromeVoxEventWatcher.speakLiveRegion_(
           evt.assertive, evt.navDescriptions);
       break;
-    case 'DOMSubtreeModified':
-      cvox.ChromeVoxEventWatcher.subtreeModifiedHandler(evt);
-      break;
   }
 };
 

chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_deprecated.js

-// Copyright 2014 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 Keeps track of live regions on the page and speaks updates
- * when they change.
- *
- */
-
-goog.provide('cvox.LiveRegionsDeprecated');
-
-goog.require('cvox.AriaUtil');
-goog.require('cvox.ChromeVox');
-goog.require('cvox.DescriptionUtil');
-goog.require('cvox.DomUtil');
-goog.require('cvox.NavDescription');
-
-/**
- * @constructor
- */
-cvox.LiveRegionsDeprecated = function() {
-};
-
-/**
- * An array of all of the elements on the page that are live regions.
- * @type {Array.<Element>}
- */
-cvox.LiveRegionsDeprecated.trackedRegions = [];
-
-/**
- * A parallel array to trackedRegions that stores the previous value of
- * each live region, represented as an array of NavDescriptions.
- * @type {Array.<Array.<cvox.NavDescription> >}
- */
-cvox.LiveRegionsDeprecated.previousRegionValue = [];
-
-/**
- * @type {Date}
- */
-cvox.LiveRegionsDeprecated.pageLoadTime = null;
-
-/**
- * Time in milliseconds after initial page load to ignore live region
- * updates, to avoid announcing regions as they're initially created.
- * The exception is alerts, they're announced when a page is loaded.
- * @type {number}
- * @const
- */
-cvox.LiveRegionsDeprecated.INITIAL_SILENCE_MS = 2000;
-
-/**
- * @param {Date} pageLoadTime The time the page was loaded. Live region
- *     updates within the first INITIAL_SILENCE_MS milliseconds are ignored.
- * @param {number} queueMode Interrupt or flush.  Polite live region
- *   changes always queue.
- * @param {boolean} disableSpeak true if change announcement should be disabled.
- * @return {boolean} true if any regions announced.
- */
-cvox.LiveRegionsDeprecated.init = function(pageLoadTime, queueMode, disableSpeak) {
-  if (queueMode == undefined) {
-    queueMode = cvox.AbstractTts.QUEUE_MODE_FLUSH;
-  }
-
-  cvox.LiveRegionsDeprecated.pageLoadTime = pageLoadTime;
-
-  var anyRegionsAnnounced = false;
-  var regions = cvox.AriaUtil.getLiveRegions(document.body);
-  for (var i = 0; i < regions.length; i++) {
-    if (cvox.LiveRegionsDeprecated.updateLiveRegion(regions[i], queueMode,
-                                          disableSpeak)) {
-      anyRegionsAnnounced = true;
-      queueMode = cvox.AbstractTts.QUEUE_MODE_QUEUE;
-    }
-  }
-
-  return anyRegionsAnnounced;
-};
-
-/**
- * Speak relevant changes to a live region.
- *
- * @param {Node} region The live region node that changed.
- * @param {number} queueMode Interrupt or queue. Polite live region
- *   changes always queue.
- * @param {boolean} disableSpeak true if change announcement should be disabled.
- * @return {boolean} true if the region announced a change.
- */
-cvox.LiveRegionsDeprecated.updateLiveRegion = function(region, queueMode, disableSpeak) {
-  if (cvox.AriaUtil.getAriaBusy(region)) {
-    return false;
-  }
-
-  // Make sure it's visible.
-  if (!cvox.DomUtil.isVisible(region)) {
-    return false;
-  }
-
-  // Retrieve the previous value of this region if we've tracked it
-  // before, otherwise start tracking it.
-  var regionIndex = cvox.LiveRegionsDeprecated.trackedRegions.indexOf(region);
-  var previousValue;
-  if (regionIndex >= 0) {
-    previousValue = cvox.LiveRegionsDeprecated.previousRegionValue[regionIndex];
-  } else {
-    regionIndex = cvox.LiveRegionsDeprecated.trackedRegions.length;
-    previousValue = [];
-    cvox.LiveRegionsDeprecated.trackedRegions.push(region);
-    cvox.LiveRegionsDeprecated.previousRegionValue.push([]);
-  }
-
-  // Get the new value.
-  var currentValue = cvox.LiveRegionsDeprecated.buildCurrentLiveRegionValue(region);
-
-  // If the page just loaded and this is any region type other than 'alert',
-  // keep track of the new value but don't announce anything. Alerts are
-  // the exception, they're announced on page load.
-  var deltaTime = new Date() - cvox.LiveRegionsDeprecated.pageLoadTime;
-  if (cvox.AriaUtil.getRoleAttribute(region) != 'alert' &&
-      deltaTime < cvox.LiveRegionsDeprecated.INITIAL_SILENCE_MS) {
-    cvox.LiveRegionsDeprecated.previousRegionValue[regionIndex] = currentValue;
-    return false;
-  }
-
-  // Don't announce alerts on page load if their text and values consist of
-  // just whitespace.
-  if (cvox.AriaUtil.getRoleAttribute(region) == 'alert' &&
-      deltaTime < cvox.LiveRegionsDeprecated.INITIAL_SILENCE_MS) {
-    var regionText = '';
-    for (var i = 0; i < currentValue.length; i++) {
-      regionText += currentValue[i].text;
-      regionText += currentValue[i].userValue;
-    }
-    if (cvox.DomUtil.collapseWhitespace(regionText) == '') {
-      cvox.LiveRegionsDeprecated.previousRegionValue[regionIndex] = currentValue;
-      return false;
-    }
-  }
-
-  // Create maps of values in the live region for fast hash lookup.
-  var previousValueMap = {};
-  for (var i = 0; i < previousValue.length; i++) {
-    previousValueMap[previousValue[i].toString()] = true;
-  }
-  var currentValueMap = {};
-  for (i = 0; i < currentValue.length; i++) {
-    currentValueMap[currentValue[i].toString()] = true;
-  }
-
-  // Figure out the additions and removals.
-  var additions = [];
-  if (cvox.AriaUtil.getAriaRelevant(region, 'additions')) {
-    for (i = 0; i < currentValue.length; i++) {
-      if (!previousValueMap[currentValue[i].toString()]) {
-        additions.push(currentValue[i]);
-      }
-    }
-  }
-  var removals = [];
-  if (cvox.AriaUtil.getAriaRelevant(region, 'removals')) {
-    for (i = 0; i < previousValue.length; i++) {
-      if (!currentValueMap[previousValue[i].toString()]) {
-        removals.push(previousValue[i]);
-      }
-    }
-  }
-
-  // Only speak removals if they're the only change. Otherwise, when one or
-  // more removals and additions happen concurrently, treat it as a change
-  // and just speak any additions (which includes changed nodes).
-  var messages = [];
-  if (additions.length == 0 && removals.length > 0) {
-    messages = [new cvox.NavDescription({
-      context: cvox.ChromeVox.msgs.getMsg('live_regions_removed'), text: ''
-    })].concat(removals);
-  } else {
-    messages = additions;
-  }
-
-  // Store the new value of the live region.
-  cvox.LiveRegionsDeprecated.previousRegionValue[regionIndex] = currentValue;
-
-  // Return if speak is disabled or there's nothing to announce.
-  if (disableSpeak || messages.length == 0) {
-    return false;
-  }
-
-  // Announce the changes with the appropriate politeness level.
-  var live = cvox.AriaUtil.getAriaLive(region);
-  if (live == 'polite') {
-    queueMode = cvox.AbstractTts.QUEUE_MODE_QUEUE;
-  }
-  for (i = 0; i < messages.length; i++) {
-    messages[i].speak(queueMode);
-    queueMode = cvox.AbstractTts.QUEUE_MODE_QUEUE;
-  }
-
-  return true;
-};
-
-/**
- * Recursively build up the value of a live region and return it as
- * an array of NavDescriptions. Each atomic portion of the region gets a
- * single string, otherwise each leaf node gets its own string. When a region
- * changes, the sets of strings before and after are searched to determine
- * which have changed.
- *
- * @param {Node} node The root node.
- * @return {Array.<cvox.NavDescription>} An array of NavDescriptions
- *     describing atomic nodes or leaf nodes in the subtree rooted
- *     at this node.
- */
-cvox.LiveRegionsDeprecated.buildCurrentLiveRegionValue = function(node) {
-  if (cvox.AriaUtil.getAriaAtomic(node) ||
-      cvox.DomUtil.isLeafNode(node)) {
-    var description = cvox.DescriptionUtil.getDescriptionFromAncestors(
-        [node], true, cvox.ChromeVox.verbosity);
-    if (!description.isEmpty()) {
-      return [description];
-    } else {
-      return [];
-    }
-  }
-
-  var result = [];
-
-  // Start with the description of this node.
-  var description = cvox.DescriptionUtil.getDescriptionFromAncestors(
-      [node], false, cvox.ChromeVox.verbosity);
-  if (!description.isEmpty()) {
-    result.push(description);
-  }
-
-  // Recursively add descriptions of child nodes.
-  for (var i = 0; i < node.childNodes.length; i++) {
-    var child = node.childNodes[i];
-    if (cvox.DomUtil.isVisible(child, {checkAncestors: false}) &&
-        !cvox.AriaUtil.isHidden(child)) {
-      var recursiveArray = cvox.LiveRegionsDeprecated.buildCurrentLiveRegionValue(child);
-      result = result.concat(recursiveArray);
-    }
-  }
-  return result;
-};