Re-land: Refactor Select-to-speak so that mouse events are forwarded to the extension.

chrome/browser/resources/chromeos/select_to_speak/select_to_speak.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 AutomationEvent = chrome.automation.AutomationEvent;
 var AutomationNode = chrome.automation.AutomationNode;
 var EventType = chrome.automation.EventType;
 var RoleType = chrome.automation.RoleType;
 
 /**
@@ skipping 35 matching lines @@
 }
 
 /**
  * @constructor
  */
 var SelectToSpeak = function() {
   /** @private { AutomationNode } */
   this.node_ = null;
 
   /** @private { boolean } */
-  this.down_ = false;
+  this.trackingMouse_ = false;
+
+  /** @private { boolean } */
+  this.didTrackMouse_ = false;
+
+  /** @private { boolean } */
+  this.isSearchKeyDown_ = false;
+
+  /** @private { !Set<number> } */
+  this.keysCurrentlyDown_ = new Set();
+
+  /** @private { !Set<number> } */
+  this.keysPressedTogether_ = new Set();
 
   /** @private {{x: number, y: number}} */
   this.mouseStart_ = {x: 0, y: 0};
 
+  /** @private {{x: number, y: number}} */
+  this.mouseEnd_ = {x: 0, y: 0};
+
+  /** @private {AutomationRootNode} */
   chrome.automation.getDesktop(function(desktop) {
+    this.desktop_ = desktop;
+
+    // After the user selects a region of the screen, we do a hit test at
+    // the center of that box using the automation API. The result of the
+    // hit test is a MOUSE_RELEASED accessibility event.
     desktop.addEventListener(
-        EventType.MOUSE_PRESSED, this.onMousePressed_.bind(this), true);
-    desktop.addEventListener(
-        EventType.MOUSE_DRAGGED, this.onMouseDragged_.bind(this), true);
-    desktop.addEventListener(
-        EventType.MOUSE_RELEASED, this.onMouseReleased_.bind(this), true);
-    desktop.addEventListener(
-        EventType.MOUSE_CANCELED, this.onMouseCanceled_.bind(this), true);
+        EventType.MOUSE_RELEASED, this.onAutomationHitTest_.bind(this),
+        true);
   }.bind(this));
 
   /** @private { ?string } */
   this.voiceNameFromPrefs_ = null;
 
   /** @private { ?string } */
   this.voiceNameFromLocale_ = null;
 
   /** @private { Set<string> } */
   this.validVoiceNames_ = new Set();
 
   /** @private { number } */
   this.speechRate_ = 1.0;
 
   /** @const { string } */
   this.color_ = "#f73a98";
 
   this.initPreferences_();
+
+  this.setUpEventListeners_();
 };
 
+/** @const {number} */
+SelectToSpeak.SEARCH_KEY_CODE = 91;
+
+/** @const {number} */
+SelectToSpeak.CONTROL_KEY_CODE = 17;
+
 SelectToSpeak.prototype = {
   /**
    * Called when the mouse is pressed and the user is in a mode where
    * select-to-speak is capturing mouse events (for example holding down
    * Search).
    *
-   * @param {!AutomationEvent} evt
+   * @param {!Event} evt The DOM event
+   * @return {boolean} True if the default action should be performed;
+   *    we always return false because we don't want any other event
+   *    handlers to run.
    */
-  onMousePressed_: function(evt) {
-    this.down_ = true;
-    this.mouseStart_ = {x: evt.mouseX, y: evt.mouseY};
-    this.startNode_ = evt.target;
+  onMouseDown_: function(evt) {
+    if (!this.isSearchKeyDown_)
+      return false;
+
+    this.trackingMouse_ = true;
+    this.didTrackMouse_ = true;
+    this.mouseStart_ = {x: evt.screenX, y: evt.screenY};
     chrome.tts.stop();
-    this.onMouseDragged_(evt);
+
+    // Fire a hit test event on click to warm up the cache.
+    this.desktop_.hitTest(evt.screenX, evt.screenY, EventType.MOUSE_PRESSED);
+
+    this.onMouseMove_(evt);
+    return false;
   },
 
   /**
    * Called when the mouse is moved or dragged and the user is in a
    * mode where select-to-speak is capturing mouse events (for example
    * holding down Search).
    *
-   * @param {!AutomationEvent} evt
+   * @param {!Event} evt The DOM event
+   * @return {boolean} True if the default action should be performed.
    */
-  onMouseDragged_: function(evt) {
-    if (!this.down_)
-      return;
+  onMouseMove_: function(evt) {
+    if (!this.trackingMouse_)
+      return false;
 
     var rect = rectFromPoints(
         this.mouseStart_.x, this.mouseStart_.y,
-        evt.mouseX, evt.mouseY);
+        evt.screenX, evt.screenY);
     chrome.accessibilityPrivate.setFocusRing([rect], this.color_);
+    return false;
   },
 
   /**
    * Called when the mouse is released and the user is in a
    * mode where select-to-speak is capturing mouse events (for example
    * holding down Search).
    *
-   * @param {!AutomationEvent} evt
+   * @param {!Event} evt
+   * @return {boolean} True if the default action should be performed.
    */
-  onMouseReleased_: function(evt) {
-    this.onMouseDragged_(evt);
-    this.down_ = false;
+  onMouseUp_: function(evt) {
+    this.onMouseMove_(evt);
+    this.trackingMouse_ = false;
 
     chrome.accessibilityPrivate.setFocusRing([]);
 
-    // Walk up to the nearest window, web area, or dialog that the
+    this.mouseEnd_ = {x: evt.screenX, y: evt.screenY};
+    var ctrX = Math.floor((this.mouseStart_.x + this.mouseEnd_.x) / 2);
+    var ctrY = Math.floor((this.mouseStart_.y + this.mouseEnd_.y) / 2);
+
+    // Do a hit test at the center of the area the user dragged over.
+    // This will give us some context when searching the accessibility tree.
+    // The hit test will result in a EventType.MOUSE_RELEASED event being
+    // fired on the result of that hit test, which will trigger
+    // onAutomationHitTest_.
+    this.desktop_.hitTest(ctrX, ctrY, EventType.MOUSE_RELEASED);
+    return false;
+  },
+
+  /**
+   * Called in response to our hit test after the mouse is released,
+   * when the user is in a mode where select-to-speak is capturing
+   * mouse events (for example holding down Search).
+   *
+   * @param {!AutomationEvent} evt The automation event.
+   */
+  onAutomationHitTest_: function(evt) {
+    // Walk up to the nearest window, web area, toolbar, or dialog that the
     // hit node is contained inside. Only speak objects within that
     // container. In the future we might include other container-like
     // roles here.
-    var root = this.startNode_;
+    var root = evt.target;
     while (root.parent &&
         root.role != RoleType.WINDOW &&
         root.role != RoleType.ROOT_WEB_AREA &&
         root.role != RoleType.DESKTOP &&
-        root.role != RoleType.DIALOG) {
+        root.role != RoleType.DIALOG &&
+        root.role != RoleType.ALERT_DIALOG &&
+        root.role != RoleType.TOOLBAR) {
       root = root.parent;
     }
 
     var rect = rectFromPoints(
         this.mouseStart_.x, this.mouseStart_.y,
-        evt.mouseX, evt.mouseY);
+        this.mouseEnd_.x, this.mouseEnd_.y);
     var nodes = [];
     this.findAllMatching_(root, rect, nodes);
     this.startSpeechQueue_(nodes);
   },
 
   /**
-   * Called when the user cancels select-to-speak's capturing of mouse
-   * events (for example by releasing Search while the mouse is still down).
-   *
-   * @param {!AutomationEvent} evt
+   * @param {!Event} evt
    */
-  onMouseCanceled_: function(evt) {
-    this.down_ = false;
-    chrome.accessibilityPrivate.setFocusRing([]);
-    chrome.tts.stop();
+  onKeyDown_: function(evt) {
+    if (this.keysPressedTogether_.size == 0 &&
+        evt.keyCode == SelectToSpeak.SEARCH_KEY_CODE) {
+      this.isSearchKeyDown_ = true;
+    } else if (!this.trackingMouse_) {
+      this.isSearchKeyDown_ = false;
+    }
+
+    this.keysCurrentlyDown_.add(evt.keyCode);
+    this.keysPressedTogether_.add(evt.keyCode);
   },
 
   /**
+   * @param {!Event} evt
+   */
+  onKeyUp_: function(evt) {
+    if (evt.keyCode == SelectToSpeak.SEARCH_KEY_CODE) {
+      this.isSearchKeyDown_ = false;
+
+      // If we were in the middle of tracking the mouse, cancel it.
+      if (this.trackingMouse_) {
+        this.trackingMouse_ = false;
+        chrome.accessibilityPrivate.setFocusRing([]);
+        chrome.tts.stop();
+      }
+    }
+
+    // Stop speech when the user taps and releases Control or Search
+    // without using the mouse or pressing any other keys along the way.
+    if (!this.didTrackMouse_ &&
+        (evt.keyCode == SelectToSpeak.SEARCH_KEY_CODE ||
+         evt.keyCode == SelectToSpeak.CONTROL_KEY_CODE) &&
+        this.keysPressedTogether_.has(evt.keyCode) &&
+        this.keysPressedTogether_.size == 1) {
+      this.trackingMouse_ = false;
+      chrome.accessibilityPrivate.setFocusRing([]);
+      chrome.tts.stop();
+    }
+
+    this.keysCurrentlyDown_.delete(evt.keyCode);
+    if (this.keysCurrentlyDown_.size == 0) {
+      this.keysPressedTogether_.clear();
+      this.didTrackMouse_ = false;
+    }
+  },
+
+  /**
+   * Set up event listeners for mouse and keyboard events. These are
+   * forwarded to us from the SelectToSpeakEventHandler so they should
+   * be interpreted as global events on the whole screen, not local to
+   * any particular window.
+   */
+  setUpEventListeners_: function() {
+    document.addEventListener('keydown', this.onKeyDown_.bind(this));
+    document.addEventListener('keyup', this.onKeyUp_.bind(this));
+    document.addEventListener('mousedown', this.onMouseDown_.bind(this));
+    document.addEventListener('mousemove', this.onMouseMove_.bind(this));
+    document.addEventListener('mouseup', this.onMouseUp_.bind(this));
+  },
+
+  /**
    * Finds all nodes within the subtree rooted at |node| that overlap
    * a given rectangle.
    * @param {AutomationNode} node The starting node.
    * @param {{left: number, top: number, width: number, height: number}} rect
    *     The bounding box to search.
    * @param {Array<AutomationNode>} nodes The matching node array to be
    *     populated.
    * @return {boolean} True if any matches are found.
    */
   findAllMatching_: function(node, rect, nodes) {
@@ skipping 96 matching lines @@
     this.updateDefaultVoice_();
     window.speechSynthesis.onvoiceschanged = (function() {
       this.updateDefaultVoice_();
     }).bind(this);
   },
 
   /**
    * Get the list of TTS voices, and set the default voice if not already set.
    */
   updateDefaultVoice_: function() {
-    console.log('updateDefaultVoice_ ' + this.down_);
     var uiLocale = chrome.i18n.getMessage('@@ui_locale');
     uiLocale = uiLocale.replace('_', '-').toLowerCase();
 
     chrome.tts.getVoices((function(voices) {
       console.log('updateDefaultVoice_ voices: ' + voices.length);
       this.validVoiceNames_ = new Set();
 
       if (voices.length == 0)
         return;
 
@@ skipping 17 matching lines @@
       this.voiceNameFromLocale_ = voices[0].voiceName;
 
       chrome.storage.sync.get(['voice'], (function(prefs) {
         if (!prefs['voice']) {
           chrome.storage.sync.set({'voice': voices[0].voiceName});
         }
       }).bind(this));
     }).bind(this));
   }
 };