Add m-esr52 at 52.6.0

1 files changed, 2329 insertions, 0 deletions

diff --git a/accessible/tests/mochitest/events.js b/accessible/tests/mochitest/events.js
new file mode 100644
index 000000000..d1e5ec8a0
--- /dev/null
+++ b/accessible/tests/mochitest/events.js
@@ -0,0 +1,2329 @@
+////////////////////////////////////////////////////////////////////////////////
+// Constants
+
+const EVENT_ALERT = nsIAccessibleEvent.EVENT_ALERT;
+const EVENT_DESCRIPTION_CHANGE = nsIAccessibleEvent.EVENT_DESCRIPTION_CHANGE;
+const EVENT_DOCUMENT_LOAD_COMPLETE = nsIAccessibleEvent.EVENT_DOCUMENT_LOAD_COMPLETE;
+const EVENT_DOCUMENT_RELOAD = nsIAccessibleEvent.EVENT_DOCUMENT_RELOAD;
+const EVENT_DOCUMENT_LOAD_STOPPED = nsIAccessibleEvent.EVENT_DOCUMENT_LOAD_STOPPED;
+const EVENT_HIDE = nsIAccessibleEvent.EVENT_HIDE;
+const EVENT_FOCUS = nsIAccessibleEvent.EVENT_FOCUS;
+const EVENT_NAME_CHANGE = nsIAccessibleEvent.EVENT_NAME_CHANGE;
+const EVENT_MENU_START = nsIAccessibleEvent.EVENT_MENU_START;
+const EVENT_MENU_END = nsIAccessibleEvent.EVENT_MENU_END;
+const EVENT_MENUPOPUP_START = nsIAccessibleEvent.EVENT_MENUPOPUP_START;
+const EVENT_MENUPOPUP_END = nsIAccessibleEvent.EVENT_MENUPOPUP_END;
+const EVENT_OBJECT_ATTRIBUTE_CHANGED = nsIAccessibleEvent.EVENT_OBJECT_ATTRIBUTE_CHANGED;
+const EVENT_REORDER = nsIAccessibleEvent.EVENT_REORDER;
+const EVENT_SCROLLING_START = nsIAccessibleEvent.EVENT_SCROLLING_START;
+const EVENT_SELECTION = nsIAccessibleEvent.EVENT_SELECTION;
+const EVENT_SELECTION_ADD = nsIAccessibleEvent.EVENT_SELECTION_ADD;
+const EVENT_SELECTION_REMOVE = nsIAccessibleEvent.EVENT_SELECTION_REMOVE;
+const EVENT_SELECTION_WITHIN = nsIAccessibleEvent.EVENT_SELECTION_WITHIN;
+const EVENT_SHOW = nsIAccessibleEvent.EVENT_SHOW;
+const EVENT_STATE_CHANGE = nsIAccessibleEvent.EVENT_STATE_CHANGE;
+const EVENT_TEXT_ATTRIBUTE_CHANGED = nsIAccessibleEvent.EVENT_TEXT_ATTRIBUTE_CHANGED;
+const EVENT_TEXT_CARET_MOVED = nsIAccessibleEvent.EVENT_TEXT_CARET_MOVED;
+const EVENT_TEXT_INSERTED = nsIAccessibleEvent.EVENT_TEXT_INSERTED;
+const EVENT_TEXT_REMOVED = nsIAccessibleEvent.EVENT_TEXT_REMOVED;
+const EVENT_TEXT_SELECTION_CHANGED = nsIAccessibleEvent.EVENT_TEXT_SELECTION_CHANGED;
+const EVENT_VALUE_CHANGE = nsIAccessibleEvent.EVENT_VALUE_CHANGE;
+const EVENT_TEXT_VALUE_CHANGE = nsIAccessibleEvent.EVENT_TEXT_VALUE_CHANGE;
+const EVENT_VIRTUALCURSOR_CHANGED = nsIAccessibleEvent.EVENT_VIRTUALCURSOR_CHANGED;
+
+const kNotFromUserInput = 0;
+const kFromUserInput = 1;
+
+////////////////////////////////////////////////////////////////////////////////
+// General
+
+Components.utils.import("resource://gre/modules/Services.jsm");
+
+/**
+ * Set up this variable to dump events into DOM.
+ */
+var gA11yEventDumpID = "";
+
+/**
+ * Set up this variable to dump event processing into console.
+ */
+var gA11yEventDumpToConsole = false;
+
+/**
+ * Set up this variable to dump event processing into error console.
+ */
+var gA11yEventDumpToAppConsole = false;
+
+/**
+ * Semicolon separated set of logging features.
+ */
+var gA11yEventDumpFeature = "";
+
+/**
+ * Executes the function when requested event is handled.
+ *
+ * @param aEventType  [in] event type
+ * @param aTarget     [in] event target
+ * @param aFunc       [in] function to call when event is handled
+ * @param aContext    [in, optional] object in which context the function is
+ *                    called
+ * @param aArg1       [in, optional] argument passed into the function
+ * @param aArg2       [in, optional] argument passed into the function
+ */
+function waitForEvent(aEventType, aTargetOrFunc, aFunc, aContext, aArg1, aArg2)
+{
+  var handler = {
+    handleEvent: function handleEvent(aEvent) {
+
+      var target = aTargetOrFunc;
+      if (typeof aTargetOrFunc == "function")
+        target = aTargetOrFunc.call();
+
+      if (target) {
+        if (target instanceof nsIAccessible &&
+            target != aEvent.accessible)
+          return;
+
+        if (target instanceof nsIDOMNode &&
+            target != aEvent.DOMNode)
+          return;
+      }
+
+      unregisterA11yEventListener(aEventType, this);
+
+      window.setTimeout(
+        function ()
+        {
+          aFunc.call(aContext, aArg1, aArg2);
+        },
+        0
+      );
+    }
+  };
+
+  registerA11yEventListener(aEventType, handler);
+}
+
+/**
+ * Generate mouse move over image map what creates image map accessible (async).
+ * See waitForImageMap() function.
+ */
+function waveOverImageMap(aImageMapID)
+{
+  var imageMapNode = getNode(aImageMapID);
+  synthesizeMouse(imageMapNode, 10, 10, { type: "mousemove" },
+                  imageMapNode.ownerDocument.defaultView);
+}
+
+/**
+ * Call the given function when the tree of the given image map is built.
+ */
+function waitForImageMap(aImageMapID, aTestFunc)
+{
+  waveOverImageMap(aImageMapID);
+
+  var imageMapAcc = getAccessible(aImageMapID);
+  if (imageMapAcc.firstChild)
+    return aTestFunc();
+
+  waitForEvent(EVENT_REORDER, imageMapAcc, aTestFunc);
+}
+
+/**
+ * Register accessibility event listener.
+ *
+ * @param aEventType     the accessible event type (see nsIAccessibleEvent for
+ *                       available constants).
+ * @param aEventHandler  event listener object, when accessible event of the
+ *                       given type is handled then 'handleEvent' method of
+ *                       this object is invoked with nsIAccessibleEvent object
+ *                       as the first argument.
+ */
+function registerA11yEventListener(aEventType, aEventHandler)
+{
+  listenA11yEvents(true);
+  addA11yEventListener(aEventType, aEventHandler);
+}
+
+/**
+ * Unregister accessibility event listener. Must be called for every registered
+ * event listener (see registerA11yEventListener() function) when the listener
+ * is not needed.
+ */
+function unregisterA11yEventListener(aEventType, aEventHandler)
+{
+  removeA11yEventListener(aEventType, aEventHandler);
+  listenA11yEvents(false);
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Event queue
+
+/**
+ * Return value of invoke method of invoker object. Indicates invoker was unable
+ * to prepare action.
+ */
+const INVOKER_ACTION_FAILED = 1;
+
+/**
+ * Return value of eventQueue.onFinish. Indicates eventQueue should not finish
+ * tests.
+ */
+const DO_NOT_FINISH_TEST = 1;
+
+/**
+ * Creates event queue for the given event type. The queue consists of invoker
+ * objects, each of them generates the event of the event type. When queue is
+ * started then every invoker object is asked to generate event after timeout.
+ * When event is caught then current invoker object is asked to check whether
+ * event was handled correctly.
+ *
+ * Invoker interface is:
+ *
+ *   var invoker = {
+ *     // Generates accessible event or event sequence. If returns
+ *     // INVOKER_ACTION_FAILED constant then stop tests.
+ *     invoke: function(){},
+ *
+ *     // [optional] Invoker's check of handled event for correctness.
+ *     check: function(aEvent){},
+ *
+ *     // [optional] Invoker's check before the next invoker is proceeded.
+ *     finalCheck: function(aEvent){},
+ *
+ *     // [optional] Is called when event of any registered type is handled.
+ *     debugCheck: function(aEvent){},
+ *
+ *     // [ignored if 'eventSeq' is defined] DOM node event is generated for
+ *     // (used in the case when invoker expects single event).
+ *     DOMNode getter: function() {},
+ *
+ *     // [optional] if true then event sequences are ignored (no failure if
+ *     // sequences are empty). Use you need to invoke an action, do some check
+ *     // after timeout and proceed a next invoker.
+ *     noEventsOnAction getter: function() {},
+ *
+ *     // Array of checker objects defining expected events on invoker's action.
+ *     //
+ *     // Checker object interface:
+ *     //
+ *     // var checker = {
+ *     //   * DOM or a11y event type. *
+ *     //   type getter: function() {},
+ *     //
+ *     //   * DOM node or accessible. *
+ *     //   target getter: function() {},
+ *     //
+ *     //   * DOM event phase (false - bubbling). *
+ *     //   phase getter: function() {},
+ *     //
+ *     //   * Callback, called to match handled event. *
+ *     //   match : function(aEvent) {},
+ *     //
+ *     //   * Callback, called when event is handled
+ *     //   check: function(aEvent) {},
+ *     //
+ *     //   * Checker ID *
+ *     //   getID: function() {},
+ *     //
+ *     //   * Event that don't have predefined order relative other events. *
+ *     //   async getter: function() {},
+ *     //
+ *     //   * Event that is not expected. *
+ *     //   unexpected getter: function() {},
+ *     //
+ *     //   * No other event of the same type is not allowed. *
+ *     //   unique getter: function() {}
+ *     // };
+ *     eventSeq getter() {},
+ *
+ *     // Array of checker objects defining unexpected events on invoker's
+ *     // action.
+ *     unexpectedEventSeq getter() {},
+ *
+ *     // The ID of invoker.
+ *     getID: function(){} // returns invoker ID
+ *   };
+ *
+ *   // Used to add a possible scenario of expected/unexpected events on
+ *   // invoker's action.
+ *  defineScenario(aInvokerObj, aEventSeq, aUnexpectedEventSeq)
+ *
+ *
+ * @param  aEventType  [in, optional] the default event type (isn't used if
+ *                      invoker defines eventSeq property).
+ */
+function eventQueue(aEventType)
+{
+  // public
+
+  /**
+   * Add invoker object into queue.
+   */
+  this.push = function eventQueue_push(aEventInvoker)
+  {
+    this.mInvokers.push(aEventInvoker);
+  }
+
+  /**
+   * Start the queue processing.
+   */
+  this.invoke = function eventQueue_invoke()
+  {
+    listenA11yEvents(true);
+
+    // XXX: Intermittent test_events_caretmove.html fails withouth timeout,
+    // see bug 474952.
+    this.processNextInvokerInTimeout(true);
+  }
+
+  /**
+   * This function is called when all events in the queue were handled.
+   * Override it if you need to be notified of this.
+   */
+  this.onFinish = function eventQueue_finish()
+  {
+  }
+
+  // private
+
+  /**
+   * Process next invoker.
+   */
+  this.processNextInvoker = function eventQueue_processNextInvoker()
+  {
+    // Some scenario was matched, we wait on next invoker processing.
+    if (this.mNextInvokerStatus == kInvokerCanceled) {
+      this.setInvokerStatus(kInvokerNotScheduled,
+                            "scenario was matched, wait for next invoker activation");
+      return;
+    }
+
+    this.setInvokerStatus(kInvokerNotScheduled, "the next invoker is processed now");
+
+    // Finish processing of the current invoker if any.
+    var testFailed = false;
+
+    var invoker = this.getInvoker();
+    if (invoker) {
+      if ("finalCheck" in invoker)
+        invoker.finalCheck();
+
+      if (this.mScenarios && this.mScenarios.length) {
+        var matchIdx = -1;
+        for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+          var eventSeq = this.mScenarios[scnIdx];
+          if (!this.areExpectedEventsLeft(eventSeq)) {
+            for (var idx = 0; idx < eventSeq.length; idx++) {
+              var checker = eventSeq[idx];
+              if (checker.unexpected && checker.wasCaught ||
+                  !checker.unexpected && checker.wasCaught != 1) {
+                break;
+              }
+            }
+
+            // Ok, we have matched scenario. Report it was completed ok. In
+            // case of empty scenario guess it was matched but if later we
+            // find out that non empty scenario was matched then it will be
+            // a final match.
+            if (idx == eventSeq.length) {
+              if (matchIdx != -1 && eventSeq.length > 0 &&
+                  this.mScenarios[matchIdx].length > 0) {
+                ok(false,
+                   "We have a matched scenario at index " + matchIdx + " already.");
+              }
+
+              if (matchIdx == -1 || eventSeq.length > 0)
+                matchIdx = scnIdx;
+
+              // Report everything is ok.
+              for (var idx = 0; idx < eventSeq.length; idx++) {
+                var checker = eventSeq[idx];
+
+                var typeStr = eventQueue.getEventTypeAsString(checker);
+                var msg = "Test with ID = '" + this.getEventID(checker) +
+                  "' succeed. ";
+
+                if (checker.unexpected) {
+                  ok(true, msg + `There's no unexpected '${typeStr}' event.`);
+                }
+                else {
+                  if (checker.todo) {
+                    todo(false, `Todo event '${typeStr}' was caught`);
+                  }
+                  else {
+                    ok(true, `${msg} Event '${typeStr}' was handled.`);
+                  }
+                }
+              }
+            }
+          }
+        }
+
+        // We don't have completely matched scenario. Report each failure/success
+        // for every scenario.
+        if (matchIdx == -1) {
+          testFailed = true;
+          for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+            var eventSeq = this.mScenarios[scnIdx];
+            for (var idx = 0; idx < eventSeq.length; idx++) {
+              var checker = eventSeq[idx];
+
+              var typeStr = eventQueue.getEventTypeAsString(checker);
+              var msg = "Scenario #" + scnIdx + " of test with ID = '" +
+                this.getEventID(checker) + "' failed. ";
+
+              if (checker.wasCaught > 1)
+                ok(false, msg + "Dupe " + typeStr + " event.");
+
+              if (checker.unexpected) {
+                if (checker.wasCaught) {
+                  ok(false, msg + "There's unexpected " + typeStr + " event.");
+                }
+              }
+              else if (!checker.wasCaught) {
+                var rf = checker.todo ? todo : ok;
+                rf(false, `${msg} '${typeStr} event is missed.`);
+              }
+            }
+          }
+        }
+      }
+    }
+
+    this.clearEventHandler();
+
+    // Check if need to stop the test.
+    if (testFailed || this.mIndex == this.mInvokers.length - 1) {
+      listenA11yEvents(false);
+
+      var res = this.onFinish();
+      if (res != DO_NOT_FINISH_TEST)
+        SimpleTest.executeSoon(SimpleTest.finish);
+
+      return;
+    }
+
+    // Start processing of next invoker.
+    invoker = this.getNextInvoker();
+
+    // Set up event listeners. Process a next invoker if no events were added.
+    if (!this.setEventHandler(invoker)) {
+      this.processNextInvoker();
+      return;
+    }
+
+    if (gLogger.isEnabled()) {
+      gLogger.logToConsole("Event queue: \n  invoke: " + invoker.getID());
+      gLogger.logToDOM("EQ: invoke: " + invoker.getID(), true);
+    }
+
+    var infoText = "Invoke the '" + invoker.getID() + "' test { ";
+    var scnCount = this.mScenarios ? this.mScenarios.length : 0;
+    for (var scnIdx = 0; scnIdx < scnCount; scnIdx++) {
+      infoText += "scenario #" + scnIdx + ": ";
+      var eventSeq = this.mScenarios[scnIdx];
+      for (var idx = 0; idx < eventSeq.length; idx++) {
+        infoText += eventSeq[idx].unexpected ? "un" : "" +
+          "expected '" + eventQueue.getEventTypeAsString(eventSeq[idx]) +
+          "' event; ";
+      }
+    }
+    infoText += " }";
+    info(infoText);
+
+    if (invoker.invoke() == INVOKER_ACTION_FAILED) {
+      // Invoker failed to prepare action, fail and finish tests.
+      this.processNextInvoker();
+      return;
+    }
+
+    if (this.hasUnexpectedEventsScenario())
+      this.processNextInvokerInTimeout(true);
+  }
+
+  this.processNextInvokerInTimeout =
+    function eventQueue_processNextInvokerInTimeout(aUncondProcess)
+  {
+    this.setInvokerStatus(kInvokerPending, "Process next invoker in timeout");
+
+    // No need to wait extra timeout when a) we know we don't need to do that
+    // and b) there's no any single unexpected event.
+    if (!aUncondProcess && this.areAllEventsExpected()) {
+      // We need delay to avoid events coalesce from different invokers.
+      var queue = this;
+      SimpleTest.executeSoon(function() { queue.processNextInvoker(); });
+      return;
+    }
+
+    // Check in timeout invoker didn't fire registered events.
+    window.setTimeout(function(aQueue) { aQueue.processNextInvoker(); }, 300,
+                      this);
+  }
+
+  /**
+   * Handle events for the current invoker.
+   */
+  this.handleEvent = function eventQueue_handleEvent(aEvent)
+  {
+    var invoker = this.getInvoker();
+    if (!invoker) // skip events before test was started
+      return;
+
+    if (!this.mScenarios) {
+      // Bad invoker object, error will be reported before processing of next
+      // invoker in the queue.
+      this.processNextInvoker();
+      return;
+    }
+
+    if ("debugCheck" in invoker)
+      invoker.debugCheck(aEvent);
+
+    for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+      var eventSeq = this.mScenarios[scnIdx];
+      for (var idx = 0; idx < eventSeq.length; idx++) {
+        var checker = eventSeq[idx];
+
+        // Search through handled expected events to report error if one of them
+        // is handled for a second time.
+        if (!checker.unexpected && (checker.wasCaught > 0) &&
+            eventQueue.isSameEvent(checker, aEvent)) {
+          checker.wasCaught++;
+          continue;
+        }
+
+        // Search through unexpected events, any match results in error report
+        // after this invoker processing (in case of matched scenario only).
+        if (checker.unexpected && eventQueue.compareEvents(checker, aEvent)) {
+          checker.wasCaught++;
+          continue;
+        }
+
+        // Report an error if we hanlded not expected event of unique type
+        // (i.e. event types are matched, targets differs).
+        if (!checker.unexpected && checker.unique &&
+            eventQueue.compareEventTypes(checker, aEvent)) {
+          var isExppected = false;
+          for (var jdx = 0; jdx < eventSeq.length; jdx++) {
+            isExpected = eventQueue.compareEvents(eventSeq[jdx], aEvent);
+            if (isExpected)
+              break;
+          }
+
+          if (!isExpected) {
+            ok(false,
+               "Unique type " +
+               eventQueue.getEventTypeAsString(checker) + " event was handled.");
+          }
+        }
+      }
+    }
+
+    var hasMatchedCheckers = false;
+    for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+      var eventSeq = this.mScenarios[scnIdx];
+
+      // Check if handled event matches expected sync event.
+      var nextChecker = this.getNextExpectedEvent(eventSeq);
+      if (nextChecker) {
+        if (eventQueue.compareEvents(nextChecker, aEvent)) {
+          this.processMatchedChecker(aEvent, nextChecker, scnIdx, eventSeq.idx);
+          hasMatchedCheckers = true;
+          continue;
+        }
+      }
+
+      // Check if handled event matches any expected async events.
+      var haveUnmatchedAsync = false;
+      for (idx = 0; idx < eventSeq.length; idx++) {
+        if (eventSeq[idx] instanceof orderChecker && haveUnmatchedAsync) {
+            break;
+        }
+
+        if (!eventSeq[idx].wasCaught) {
+          haveUnmatchedAsync = true;
+        }
+
+        if (!eventSeq[idx].unexpected && eventSeq[idx].async) {
+          if (eventQueue.compareEvents(eventSeq[idx], aEvent)) {
+            this.processMatchedChecker(aEvent, eventSeq[idx], scnIdx, idx);
+            hasMatchedCheckers = true;
+            break;
+          }
+        }
+      }
+    }
+
+    if (hasMatchedCheckers) {
+      var invoker = this.getInvoker();
+      if ("check" in invoker)
+        invoker.check(aEvent);
+    }
+
+    for (idx = 0; idx < eventSeq.length; idx++) {
+      if (!eventSeq[idx].wasCaught) {
+        if (eventSeq[idx] instanceof orderChecker) {
+          eventSeq[idx].wasCaught++;
+        } else {
+          break;
+        }
+      }
+    }
+
+    // If we don't have more events to wait then schedule next invoker.
+    if (this.hasMatchedScenario()) {
+      if (this.mNextInvokerStatus == kInvokerNotScheduled) {
+        this.processNextInvokerInTimeout();
+
+      } else if (this.mNextInvokerStatus == kInvokerCanceled) {
+        this.setInvokerStatus(kInvokerPending,
+                              "Full match. Void the cancelation of next invoker processing");
+      }
+      return;
+    }
+
+    // If we have scheduled a next invoker then cancel in case of match.
+    if ((this.mNextInvokerStatus == kInvokerPending) && hasMatchedCheckers) {
+      this.setInvokerStatus(kInvokerCanceled,
+                            "Cancel the scheduled invoker in case of match");
+    }
+  }
+
+  // Helpers
+  this.processMatchedChecker =
+    function eventQueue_function(aEvent, aMatchedChecker, aScenarioIdx, aEventIdx)
+  {
+    aMatchedChecker.wasCaught++;
+
+    if ("check" in aMatchedChecker)
+      aMatchedChecker.check(aEvent);
+
+    eventQueue.logEvent(aEvent, aMatchedChecker, aScenarioIdx, aEventIdx,
+                        this.areExpectedEventsLeft(),
+                        this.mNextInvokerStatus);
+  }
+
+  this.getNextExpectedEvent =
+    function eventQueue_getNextExpectedEvent(aEventSeq)
+  {
+    if (!("idx" in aEventSeq))
+      aEventSeq.idx = 0;
+
+    while (aEventSeq.idx < aEventSeq.length &&
+           (aEventSeq[aEventSeq.idx].unexpected ||
+            aEventSeq[aEventSeq.idx].todo ||
+            aEventSeq[aEventSeq.idx].async ||
+            aEventSeq[aEventSeq.idx] instanceof orderChecker ||
+            aEventSeq[aEventSeq.idx].wasCaught > 0)) {
+      aEventSeq.idx++;
+    }
+
+    return aEventSeq.idx != aEventSeq.length ? aEventSeq[aEventSeq.idx] : null;
+  }
+
+  this.areExpectedEventsLeft =
+    function eventQueue_areExpectedEventsLeft(aScenario)
+  {
+    function scenarioHasUnhandledExpectedEvent(aEventSeq)
+    {
+      // Check if we have unhandled async (can be anywhere in the sequance) or
+      // sync expcected events yet.
+      for (var idx = 0; idx < aEventSeq.length; idx++) {
+        if (!aEventSeq[idx].unexpected && !aEventSeq[idx].todo &&
+            !aEventSeq[idx].wasCaught && !(aEventSeq[idx] instanceof orderChecker))
+          return true;
+      }
+
+      return false;
+    }
+
+    if (aScenario)
+      return scenarioHasUnhandledExpectedEvent(aScenario);
+
+    for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+      var eventSeq = this.mScenarios[scnIdx];
+      if (scenarioHasUnhandledExpectedEvent(eventSeq))
+        return true;
+    }
+    return false;
+  }
+
+  this.areAllEventsExpected =
+    function eventQueue_areAllEventsExpected()
+  {
+    for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+      var eventSeq = this.mScenarios[scnIdx];
+      for (var idx = 0; idx < eventSeq.length; idx++) {
+        if (eventSeq[idx].unexpected || eventSeq[idx].todo)
+          return false;
+      }
+    }
+
+    return true;
+  }
+
+  this.isUnexpectedEventScenario =
+    function eventQueue_isUnexpectedEventsScenario(aScenario)
+  {
+    for (var idx = 0; idx < aScenario.length; idx++) {
+      if (!aScenario[idx].unexpected && !aScenario[idx].todo)
+        break;
+    }
+
+    return idx == aScenario.length;
+  }
+
+  this.hasUnexpectedEventsScenario =
+    function eventQueue_hasUnexpectedEventsScenario()
+  {
+    if (this.getInvoker().noEventsOnAction)
+      return true;
+
+    for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+      if (this.isUnexpectedEventScenario(this.mScenarios[scnIdx]))
+        return true;
+    }
+
+    return false;
+  }
+
+  this.hasMatchedScenario =
+    function eventQueue_hasMatchedScenario()
+  {
+    for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+      var scn = this.mScenarios[scnIdx];
+      if (!this.isUnexpectedEventScenario(scn) && !this.areExpectedEventsLeft(scn))
+        return true;
+    }
+    return false;
+  }
+
+  this.getInvoker = function eventQueue_getInvoker()
+  {
+    return this.mInvokers[this.mIndex];
+  }
+
+  this.getNextInvoker = function eventQueue_getNextInvoker()
+  {
+    return this.mInvokers[++this.mIndex];
+  }
+
+  this.setEventHandler = function eventQueue_setEventHandler(aInvoker)
+  {
+    if (!("scenarios" in aInvoker) || aInvoker.scenarios.length == 0) {
+      var eventSeq = aInvoker.eventSeq;
+      var unexpectedEventSeq = aInvoker.unexpectedEventSeq;
+      if (!eventSeq && !unexpectedEventSeq && this.mDefEventType)
+        eventSeq = [ new invokerChecker(this.mDefEventType, aInvoker.DOMNode) ];
+
+      if (eventSeq || unexpectedEventSeq)
+        defineScenario(aInvoker, eventSeq, unexpectedEventSeq);
+    }
+
+    if (aInvoker.noEventsOnAction)
+      return true;
+
+    this.mScenarios = aInvoker.scenarios;
+    if (!this.mScenarios || !this.mScenarios.length) {
+      ok(false, "Broken invoker '" + aInvoker.getID() + "'");
+      return false;
+    }
+
+    // Register event listeners.
+    for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+      var eventSeq = this.mScenarios[scnIdx];
+
+      if (gLogger.isEnabled()) {
+        var msg = "scenario #" + scnIdx +
+          ", registered events number: " + eventSeq.length;
+        gLogger.logToConsole(msg);
+        gLogger.logToDOM(msg, true);
+      }
+
+      // Do not warn about empty event sequances when more than one scenario
+      // was registered.
+      if (this.mScenarios.length == 1 && eventSeq.length == 0) {
+        ok(false,
+           "Broken scenario #" + scnIdx + " of invoker '" + aInvoker.getID() +
+           "'. No registered events");
+        return false;
+      }
+
+      for (var idx = 0; idx < eventSeq.length; idx++)
+        eventSeq[idx].wasCaught = 0;
+
+      for (var idx = 0; idx < eventSeq.length; idx++) {
+        if (gLogger.isEnabled()) {
+          var msg = "registered";
+          if (eventSeq[idx].unexpected)
+            msg += " unexpected";
+          if (eventSeq[idx].async)
+            msg += " async";
+
+          msg += ": event type: " +
+            eventQueue.getEventTypeAsString(eventSeq[idx]) +
+            ", target: " + eventQueue.getEventTargetDescr(eventSeq[idx], true);
+
+          gLogger.logToConsole(msg);
+          gLogger.logToDOM(msg, true);
+        }
+
+        var eventType = eventSeq[idx].type;
+        if (typeof eventType == "string") {
+          // DOM event
+          var target = eventSeq[idx].target;
+          if (!target) {
+            ok(false, "no target for DOM event!");
+            return false;
+          }
+          var phase = eventQueue.getEventPhase(eventSeq[idx]);
+          target.ownerDocument.addEventListener(eventType, this, phase);
+
+        } else {
+          // A11y event
+          addA11yEventListener(eventType, this);
+        }
+      }
+    }
+
+    return true;
+  }
+
+  this.clearEventHandler = function eventQueue_clearEventHandler()
+  {
+    if (!this.mScenarios)
+      return;
+
+    for (var scnIdx = 0; scnIdx < this.mScenarios.length; scnIdx++) {
+      var eventSeq = this.mScenarios[scnIdx];
+      for (var idx = 0; idx < eventSeq.length; idx++) {
+        var eventType = eventSeq[idx].type;
+        if (typeof eventType == "string") {
+          // DOM event
+          var target = eventSeq[idx].target;
+          var phase = eventQueue.getEventPhase(eventSeq[idx]);
+          target.ownerDocument.removeEventListener(eventType, this, phase);
+
+        } else {
+          // A11y event
+          removeA11yEventListener(eventType, this);
+        }
+      }
+    }
+    this.mScenarios = null;
+  }
+
+  this.getEventID = function eventQueue_getEventID(aChecker)
+  {
+    if ("getID" in aChecker)
+      return aChecker.getID();
+
+    var invoker = this.getInvoker();
+    return invoker.getID();
+  }
+
+  this.setInvokerStatus = function eventQueue_setInvokerStatus(aStatus, aLogMsg)
+  {
+    this.mNextInvokerStatus = aStatus;
+
+    // Uncomment it to debug invoker processing logic.
+    //gLogger.log(eventQueue.invokerStatusToMsg(aStatus, aLogMsg));
+  }
+
+  this.mDefEventType = aEventType;
+
+  this.mInvokers = new Array();
+  this.mIndex = -1;
+  this.mScenarios = null;
+
+  this.mNextInvokerStatus = kInvokerNotScheduled;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// eventQueue static members and constants
+
+const kInvokerNotScheduled = 0;
+const kInvokerPending = 1;
+const kInvokerCanceled = 2;
+
+eventQueue.getEventTypeAsString =
+  function eventQueue_getEventTypeAsString(aEventOrChecker)
+{
+  if (aEventOrChecker instanceof nsIDOMEvent)
+    return aEventOrChecker.type;
+
+  if (aEventOrChecker instanceof nsIAccessibleEvent)
+    return eventTypeToString(aEventOrChecker.eventType);
+
+  return (typeof aEventOrChecker.type == "string") ?
+    aEventOrChecker.type : eventTypeToString(aEventOrChecker.type);
+}
+
+eventQueue.getEventTargetDescr =
+  function eventQueue_getEventTargetDescr(aEventOrChecker, aDontForceTarget)
+{
+  if (aEventOrChecker instanceof nsIDOMEvent)
+    return prettyName(aEventOrChecker.originalTarget);
+
+  if (aEventOrChecker instanceof nsIDOMEvent)
+    return prettyName(aEventOrChecker.accessible);
+
+  var descr = aEventOrChecker.targetDescr;
+  if (descr)
+    return descr;
+
+  if (aDontForceTarget)
+    return "no target description";
+
+  var target = ("target" in aEventOrChecker) ? aEventOrChecker.target : null;
+  return prettyName(target);
+}
+
+eventQueue.getEventPhase = function eventQueue_getEventPhase(aChecker)
+{
+  return ("phase" in aChecker) ? aChecker.phase : true;
+}
+
+eventQueue.compareEventTypes =
+  function eventQueue_compareEventTypes(aChecker, aEvent)
+{
+  var eventType = (aEvent instanceof nsIDOMEvent) ?
+    aEvent.type : aEvent.eventType;
+  return aChecker.type == eventType;
+}
+
+eventQueue.compareEvents = function eventQueue_compareEvents(aChecker, aEvent)
+{
+  if (!eventQueue.compareEventTypes(aChecker, aEvent))
+    return false;
+
+  // If checker provides "match" function then allow the checker to decide
+  // whether event is matched.
+  if ("match" in aChecker)
+    return aChecker.match(aEvent);
+
+  var target1 = aChecker.target;
+  if (target1 instanceof nsIAccessible) {
+    var target2 = (aEvent instanceof nsIDOMEvent) ?
+      getAccessible(aEvent.target) : aEvent.accessible;
+
+    return target1 == target2;
+  }
+
+  // If original target isn't suitable then extend interface to support target
+  // (original target is used in test_elm_media.html).
+  var target2 = (aEvent instanceof nsIDOMEvent) ?
+    aEvent.originalTarget : aEvent.DOMNode;
+  return target1 == target2;
+}
+
+eventQueue.isSameEvent = function eventQueue_isSameEvent(aChecker, aEvent)
+{
+  // We don't have stored info about handled event other than its type and
+  // target, thus we should filter text change and state change events since
+  // they may occur on the same element because of complex changes.
+  return this.compareEvents(aChecker, aEvent) &&
+    !(aEvent instanceof nsIAccessibleTextChangeEvent) &&
+    !(aEvent instanceof nsIAccessibleStateChangeEvent);
+}
+
+eventQueue.invokerStatusToMsg =
+  function eventQueue_invokerStatusToMsg(aInvokerStatus, aMsg)
+{
+  var msg = "invoker status: ";
+  switch (aInvokerStatus) {
+    case kInvokerNotScheduled:
+      msg += "not scheduled";
+      break;
+    case kInvokerPending:
+      msg += "pending";
+      break;
+    case kInvokerCanceled:
+      msg += "canceled";
+      break;
+  }
+
+  if (aMsg)
+    msg += " (" + aMsg + ")";
+
+  return msg;
+}
+
+eventQueue.logEvent = function eventQueue_logEvent(aOrigEvent, aMatchedChecker,
+                                                   aScenarioIdx, aEventIdx,
+                                                   aAreExpectedEventsLeft,
+                                                   aInvokerStatus)
+{
+  // Dump DOM event information. Skip a11y event since it is dumped by
+  // gA11yEventObserver.
+  if (aOrigEvent instanceof nsIDOMEvent) {
+    var info = "Event type: " + eventQueue.getEventTypeAsString(aOrigEvent);
+    info += ". Target: " + eventQueue.getEventTargetDescr(aOrigEvent);
+    gLogger.logToDOM(info);
+  }
+
+  var infoMsg = "unhandled expected events: " + aAreExpectedEventsLeft +
+    ", "  + eventQueue.invokerStatusToMsg(aInvokerStatus);
+
+  var currType = eventQueue.getEventTypeAsString(aMatchedChecker);
+  var currTargetDescr = eventQueue.getEventTargetDescr(aMatchedChecker);
+  var consoleMsg = "*****\nScenario " + aScenarioIdx + 
+    ", event " + aEventIdx + " matched: " + currType + "\n" + infoMsg + "\n*****";
+  gLogger.logToConsole(consoleMsg);
+
+  var emphText = "matched ";
+  var msg = "EQ event, type: " + currType + ", target: " + currTargetDescr +
+    ", " + infoMsg;
+  gLogger.logToDOM(msg, true, emphText);
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Action sequence
+
+/**
+ * Deal with action sequence. Used when you need to execute couple of actions
+ * each after other one.
+ */
+function sequence()
+{
+  /**
+   * Append new sequence item.
+   *
+   * @param  aProcessor  [in] object implementing interface
+   *                      {
+   *                        // execute item action
+   *                        process: function() {},
+   *                        // callback, is called when item was processed
+   *                        onProcessed: function() {}
+   *                      };
+   * @param  aEventType  [in] event type of expected event on item action
+   * @param  aTarget     [in] event target of expected event on item action
+   * @param  aItemID     [in] identifier of item
+   */
+  this.append = function sequence_append(aProcessor, aEventType, aTarget,
+                                         aItemID)
+  {
+    var item = new sequenceItem(aProcessor, aEventType, aTarget, aItemID);
+    this.items.push(item);
+  }
+
+  /**
+   * Process next sequence item.
+   */
+  this.processNext = function sequence_processNext()
+  {
+    this.idx++;
+    if (this.idx >= this.items.length) {
+      ok(false, "End of sequence: nothing to process!");
+      SimpleTest.finish();
+      return;
+    }
+
+    this.items[this.idx].startProcess();
+  }
+
+  this.items = new Array();
+  this.idx = -1;
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Event queue invokers
+
+/**
+ * Defines a scenario of expected/unexpected events. Each invoker can have
+ * one or more scenarios of events. Only one scenario must be completed.
+ */
+function defineScenario(aInvoker, aEventSeq, aUnexpectedEventSeq)
+{
+  if (!("scenarios" in aInvoker))
+    aInvoker.scenarios = new Array();
+
+  // Create unified event sequence concatenating expected and unexpected
+  // events.
+  if (!aEventSeq)
+    aEventSeq = [];
+
+  for (var idx = 0; idx < aEventSeq.length; idx++) {
+    aEventSeq[idx].unexpected |= false;
+    aEventSeq[idx].async |= false;
+  }
+
+  if (aUnexpectedEventSeq) {
+    for (var idx = 0; idx < aUnexpectedEventSeq.length; idx++) {
+      aUnexpectedEventSeq[idx].unexpected = true;
+      aUnexpectedEventSeq[idx].async = false;
+    }
+
+    aEventSeq = aEventSeq.concat(aUnexpectedEventSeq);
+  }
+
+  aInvoker.scenarios.push(aEventSeq);
+}
+
+
+/**
+ * Invokers defined below take a checker object (or array of checker objects).
+ * An invoker listens for default event type registered in event queue object
+ * until its checker is provided.
+ *
+ * Note, checker object or array of checker objects is optional.
+ */
+
+/**
+ * Click invoker.
+ */
+function synthClick(aNodeOrID, aCheckerOrEventSeq, aArgs)
+{
+  this.__proto__ = new synthAction(aNodeOrID, aCheckerOrEventSeq);
+
+  this.invoke = function synthClick_invoke()
+  {
+    var targetNode = this.DOMNode;
+    if (targetNode instanceof nsIDOMDocument) {
+      targetNode =
+        this.DOMNode.body ? this.DOMNode.body : this.DOMNode.documentElement;
+    }
+
+    // Scroll the node into view, otherwise synth click may fail.
+    if (targetNode instanceof nsIDOMHTMLElement) {
+      targetNode.scrollIntoView(true);
+    } else if (targetNode instanceof nsIDOMXULElement) {
+      var targetAcc = getAccessible(targetNode);
+      targetAcc.scrollTo(SCROLL_TYPE_ANYWHERE);
+    }
+
+    var x = 1, y = 1;
+    if (aArgs && ("where" in aArgs) && aArgs.where == "right") {
+      if (targetNode instanceof nsIDOMHTMLElement)
+        x = targetNode.offsetWidth - 1;
+      else if (targetNode instanceof nsIDOMXULElement)
+        x = targetNode.boxObject.width - 1;
+    }
+    synthesizeMouse(targetNode, x, y, aArgs ? aArgs : {});
+  }
+
+  this.finalCheck = function synthClick_finalCheck()
+  {
+    // Scroll top window back.
+    window.top.scrollTo(0, 0);
+  }
+
+  this.getID = function synthClick_getID()
+  {
+    return prettyName(aNodeOrID) + " click";
+  }
+}
+
+/**
+ * Mouse move invoker.
+ */
+function synthMouseMove(aID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthAction(aID, aCheckerOrEventSeq);
+
+  this.invoke = function synthMouseMove_invoke()
+  {
+    synthesizeMouse(this.DOMNode, 1, 1, { type: "mousemove" });
+    synthesizeMouse(this.DOMNode, 2, 2, { type: "mousemove" });
+  }
+
+  this.getID = function synthMouseMove_getID()
+  {
+    return prettyName(aID) + " mouse move";
+  }
+}
+
+/**
+ * General key press invoker.
+ */
+function synthKey(aNodeOrID, aKey, aArgs, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthAction(aNodeOrID, aCheckerOrEventSeq);
+
+  this.invoke = function synthKey_invoke()
+  {
+    synthesizeKey(this.mKey, this.mArgs, this.mWindow);
+  }
+
+  this.getID = function synthKey_getID()
+  {
+    var key = this.mKey;
+    switch (this.mKey) {
+      case "VK_TAB":
+        key = "tab";
+        break;
+      case "VK_DOWN":
+        key = "down";
+        break;
+      case "VK_UP":
+        key = "up";
+        break;
+      case "VK_LEFT":
+        key = "left";
+        break;
+      case "VK_RIGHT":
+        key = "right";
+        break;
+      case "VK_HOME":
+        key = "home";
+        break;
+      case "VK_END":
+        key = "end";
+        break;
+      case "VK_ESCAPE":
+        key = "escape";
+        break;
+      case "VK_RETURN":
+        key = "enter";
+        break;
+    }
+    if (aArgs) {
+      if (aArgs.shiftKey)
+        key += " shift";
+      if (aArgs.ctrlKey)
+        key += " ctrl";
+      if (aArgs.altKey)
+        key += " alt";
+    }
+    return prettyName(aNodeOrID) + " '" + key + " ' key";
+  }
+
+  this.mKey = aKey;
+  this.mArgs = aArgs ? aArgs : {};
+  this.mWindow = aArgs ? aArgs.window : null;
+}
+
+/**
+ * Tab key invoker.
+ */
+function synthTab(aNodeOrID, aCheckerOrEventSeq, aWindow)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_TAB",
+                                { shiftKey: false, window: aWindow },
+                                aCheckerOrEventSeq);
+}
+
+/**
+ * Shift tab key invoker.
+ */
+function synthShiftTab(aNodeOrID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_TAB", { shiftKey: true },
+                                aCheckerOrEventSeq);
+}
+
+/**
+ * Escape key invoker.
+ */
+function synthEscapeKey(aNodeOrID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_ESCAPE", null,
+                                aCheckerOrEventSeq);
+}
+
+/**
+ * Down arrow key invoker.
+ */
+function synthDownKey(aNodeOrID, aCheckerOrEventSeq, aArgs)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_DOWN", aArgs,
+                                aCheckerOrEventSeq);
+}
+
+/**
+ * Up arrow key invoker.
+ */
+function synthUpKey(aNodeOrID, aCheckerOrEventSeq, aArgs)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_UP", aArgs,
+                                aCheckerOrEventSeq);
+}
+
+/**
+ * Left arrow key invoker.
+ */
+function synthLeftKey(aNodeOrID, aCheckerOrEventSeq, aArgs)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_LEFT", aArgs, aCheckerOrEventSeq);
+}
+
+/**
+ * Right arrow key invoker.
+ */
+function synthRightKey(aNodeOrID, aCheckerOrEventSeq, aArgs)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_RIGHT", aArgs, aCheckerOrEventSeq);
+}
+
+/**
+ * Home key invoker.
+ */
+function synthHomeKey(aNodeOrID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_HOME", null, aCheckerOrEventSeq);
+}
+
+/**
+ * End key invoker.
+ */
+function synthEndKey(aNodeOrID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthKey(aNodeOrID, "VK_END", null, aCheckerOrEventSeq);
+}
+
+/**
+ * Enter key invoker
+ */
+function synthEnterKey(aID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthKey(aID, "VK_RETURN", null, aCheckerOrEventSeq);
+}
+
+/**
+ * Synth alt + down arrow to open combobox.
+ */
+function synthOpenComboboxKey(aID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthDownKey(aID, aCheckerOrEventSeq, { altKey: true });
+
+  this.getID = function synthOpenComboboxKey_getID()
+  {
+    return "open combobox (atl + down arrow) " + prettyName(aID);
+  }
+}
+
+/**
+ * Focus invoker.
+ */
+function synthFocus(aNodeOrID, aCheckerOrEventSeq)
+{
+  var checkerOfEventSeq =
+    aCheckerOrEventSeq ? aCheckerOrEventSeq : new focusChecker(aNodeOrID);
+  this.__proto__ = new synthAction(aNodeOrID, checkerOfEventSeq);
+
+  this.invoke = function synthFocus_invoke()
+  {
+    if (this.DOMNode instanceof Components.interfaces.nsIDOMNSEditableElement &&
+        this.DOMNode.editor ||
+        this.DOMNode instanceof Components.interfaces.nsIDOMXULTextBoxElement) {
+      this.DOMNode.selectionStart = this.DOMNode.selectionEnd = this.DOMNode.value.length;
+    }
+    this.DOMNode.focus();
+  }
+
+  this.getID = function synthFocus_getID() 
+  { 
+    return prettyName(aNodeOrID) + " focus";
+  }
+}
+
+/**
+ * Focus invoker. Focus the HTML body of content document of iframe.
+ */
+function synthFocusOnFrame(aNodeOrID, aCheckerOrEventSeq)
+{
+  var frameDoc = getNode(aNodeOrID).contentDocument;
+  var checkerOrEventSeq =
+    aCheckerOrEventSeq ? aCheckerOrEventSeq : new focusChecker(frameDoc);
+  this.__proto__ = new synthAction(frameDoc, checkerOrEventSeq);
+
+  this.invoke = function synthFocus_invoke()
+  {
+    this.DOMNode.body.focus();
+  }
+
+  this.getID = function synthFocus_getID() 
+  { 
+    return prettyName(aNodeOrID) + " frame document focus";
+  }
+}
+
+/**
+ * Change the current item when the widget doesn't have a focus.
+ */
+function changeCurrentItem(aID, aItemID)
+{
+  this.eventSeq = [ new nofocusChecker() ];
+
+  this.invoke = function changeCurrentItem_invoke()
+  {
+    var controlNode = getNode(aID);
+    var itemNode = getNode(aItemID);
+
+    // HTML
+    if (controlNode.localName == "input") {
+      if (controlNode.checked)
+        this.reportError();
+
+      controlNode.checked = true;
+      return;
+    }
+
+    if (controlNode.localName == "select") {
+      if (controlNode.selectedIndex == itemNode.index)
+        this.reportError();
+
+      controlNode.selectedIndex = itemNode.index;
+      return;
+    }
+
+    // XUL
+    if (controlNode.localName == "tree") {
+      if (controlNode.currentIndex == aItemID)
+        this.reportError();
+
+      controlNode.currentIndex = aItemID;
+      return;
+    }
+
+    if (controlNode.localName == "menulist") {
+      if (controlNode.selectedItem == itemNode)
+        this.reportError();
+
+      controlNode.selectedItem = itemNode;
+      return;
+    }
+
+    if (controlNode.currentItem == itemNode)
+      ok(false, "Error in test: proposed current item is already current" + prettyName(aID));
+
+    controlNode.currentItem = itemNode;
+  }
+
+  this.getID = function changeCurrentItem_getID()
+  {
+    return "current item change for " + prettyName(aID);
+  }
+
+  this.reportError = function changeCurrentItem_reportError()
+  {
+    ok(false,
+       "Error in test: proposed current item '" + aItemID + "' is already current");
+  }
+}
+
+/**
+ * Toggle top menu invoker.
+ */
+function toggleTopMenu(aID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthKey(aID, "VK_ALT", null,
+                                aCheckerOrEventSeq);
+
+  this.getID = function toggleTopMenu_getID()
+  {
+    return "toggle top menu on " + prettyName(aID);
+  }
+}
+
+/**
+ * Context menu invoker.
+ */
+function synthContextMenu(aID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthClick(aID, aCheckerOrEventSeq,
+                                  { button: 0, type: "contextmenu" });
+
+  this.getID = function synthContextMenu_getID()
+  {
+    return "context menu on " + prettyName(aID);
+  }
+}
+
+/**
+ * Open combobox, autocomplete and etc popup, check expandable states.
+ */
+function openCombobox(aComboboxID)
+{
+  this.eventSeq = [
+    new stateChangeChecker(STATE_EXPANDED, false, true, aComboboxID)
+  ];
+
+  this.invoke = function openCombobox_invoke()
+  {
+    getNode(aComboboxID).focus();
+    synthesizeKey("VK_DOWN", { altKey: true });
+  }
+
+  this.getID = function openCombobox_getID()
+  {
+    return "open combobox " + prettyName(aComboboxID);
+  }
+}
+
+/**
+ * Close combobox, autocomplete and etc popup, check expandable states.
+ */
+function closeCombobox(aComboboxID)
+{
+  this.eventSeq = [
+    new stateChangeChecker(STATE_EXPANDED, false, false, aComboboxID)
+  ];
+
+  this.invoke = function closeCombobox_invoke()
+  {
+    synthesizeKey("VK_ESCAPE", { });
+  }
+
+  this.getID = function closeCombobox_getID()
+  {
+    return "close combobox " + prettyName(aComboboxID);
+  }
+}
+
+
+/**
+ * Select all invoker.
+ */
+function synthSelectAll(aNodeOrID, aCheckerOrEventSeq)
+{
+  this.__proto__ = new synthAction(aNodeOrID, aCheckerOrEventSeq);
+
+  this.invoke = function synthSelectAll_invoke()
+  {
+    if (this.DOMNode instanceof Components.interfaces.nsIDOMHTMLInputElement ||
+        this.DOMNode instanceof Components.interfaces.nsIDOMXULTextBoxElement) {
+      this.DOMNode.select();
+
+    } else {
+      window.getSelection().selectAllChildren(this.DOMNode);
+    }
+  }
+
+  this.getID = function synthSelectAll_getID()
+  {
+    return aNodeOrID + " selectall";
+  }
+}
+
+/**
+ * Move the caret to the end of line.
+ */
+function moveToLineEnd(aID, aCaretOffset)
+{
+  if (MAC) {
+    this.__proto__ = new synthKey(aID, "VK_RIGHT", { metaKey: true },
+                                  new caretMoveChecker(aCaretOffset, aID));
+  } else {
+    this.__proto__ = new synthEndKey(aID,
+                                     new caretMoveChecker(aCaretOffset, aID));
+  }
+
+  this.getID = function moveToLineEnd_getID()
+  {
+    return "move to line end in " + prettyName(aID);
+  }
+}
+
+/**
+ * Move the caret to the end of previous line if any.
+ */
+function moveToPrevLineEnd(aID, aCaretOffset)
+{
+  this.__proto__ = new synthAction(aID, new caretMoveChecker(aCaretOffset, aID));
+
+  this.invoke = function moveToPrevLineEnd_invoke()
+  {
+    synthesizeKey("VK_UP", { });
+
+    if (MAC)
+      synthesizeKey("VK_RIGHT", { metaKey: true });
+    else
+      synthesizeKey("VK_END", { });
+  }
+
+  this.getID = function moveToPrevLineEnd_getID()
+  {
+    return "move to previous line end in " + prettyName(aID);
+  }
+}
+
+/**
+ * Move the caret to begining of the line.
+ */
+function moveToLineStart(aID, aCaretOffset)
+{
+  if (MAC) {
+    this.__proto__ = new synthKey(aID, "VK_LEFT", { metaKey: true },
+                                  new caretMoveChecker(aCaretOffset, aID));
+  } else {
+    this.__proto__ = new synthHomeKey(aID,
+                                      new caretMoveChecker(aCaretOffset, aID));
+  }
+
+  this.getID = function moveToLineEnd_getID()
+  {
+    return "move to line start in " + prettyName(aID);
+  }
+}
+
+/**
+ * Move the caret to begining of the text.
+ */
+function moveToTextStart(aID)
+{
+  if (MAC) {
+    this.__proto__ = new synthKey(aID, "VK_UP", { metaKey: true },
+                                  new caretMoveChecker(0, aID));
+  } else {
+    this.__proto__ = new synthKey(aID, "VK_HOME", { ctrlKey: true },
+                                  new caretMoveChecker(0, aID));
+  }
+
+  this.getID = function moveToTextStart_getID()
+  {
+    return "move to text start in " + prettyName(aID);
+  }
+}
+
+/**
+ * Move the caret in text accessible.
+ */
+function moveCaretToDOMPoint(aID, aDOMPointNodeID, aDOMPointOffset,
+                             aExpectedOffset, aFocusTargetID,
+                             aCheckFunc)
+{
+  this.target = getAccessible(aID, [nsIAccessibleText]);
+  this.DOMPointNode = getNode(aDOMPointNodeID);
+  this.focus = aFocusTargetID ? getAccessible(aFocusTargetID) : null;
+  this.focusNode = this.focus ? this.focus.DOMNode : null;
+
+  this.invoke = function moveCaretToDOMPoint_invoke()
+  {
+    if (this.focusNode)
+      this.focusNode.focus();
+
+    var selection = this.DOMPointNode.ownerDocument.defaultView.getSelection();
+    var selRange = selection.getRangeAt(0);
+    selRange.setStart(this.DOMPointNode, aDOMPointOffset);
+    selRange.collapse(true);
+
+    selection.removeRange(selRange);
+    selection.addRange(selRange);
+  }
+
+  this.getID = function moveCaretToDOMPoint_getID()
+  {
+   return "Set caret on " + prettyName(aID) + " at point: " +
+     prettyName(aDOMPointNodeID) + " node with offset " + aDOMPointOffset;
+  }
+
+  this.finalCheck = function moveCaretToDOMPoint_finalCheck()
+  {
+    if (aCheckFunc)
+      aCheckFunc.call();
+  }
+
+  this.eventSeq = [
+    new caretMoveChecker(aExpectedOffset, this.target)
+  ];
+
+  if (this.focus)
+    this.eventSeq.push(new asyncInvokerChecker(EVENT_FOCUS, this.focus));
+}
+
+/**
+ * Set caret offset in text accessible.
+ */
+function setCaretOffset(aID, aOffset, aFocusTargetID)
+{
+  this.target = getAccessible(aID, [nsIAccessibleText]);
+  this.offset = aOffset == -1 ? this.target.characterCount: aOffset;
+  this.focus = aFocusTargetID ? getAccessible(aFocusTargetID) : null;
+
+  this.invoke = function setCaretOffset_invoke()
+  {
+    this.target.caretOffset = this.offset;
+  }
+
+  this.getID = function setCaretOffset_getID()
+  {
+   return "Set caretOffset on " + prettyName(aID) + " at " + this.offset;
+  }
+
+  this.eventSeq = [
+    new caretMoveChecker(this.offset, this.target)
+  ];
+
+  if (this.focus)
+    this.eventSeq.push(new asyncInvokerChecker(EVENT_FOCUS, this.focus));
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Event queue checkers
+
+/**
+ * Common invoker checker (see eventSeq of eventQueue).
+ */
+function invokerChecker(aEventType, aTargetOrFunc, aTargetFuncArg, aIsAsync)
+{
+  this.type = aEventType;
+  this.async = aIsAsync;
+
+  this.__defineGetter__("target", invokerChecker_targetGetter);
+  this.__defineSetter__("target", invokerChecker_targetSetter);
+
+  // implementation details
+  function invokerChecker_targetGetter()
+  {
+    if (typeof this.mTarget == "function")
+      return this.mTarget.call(null, this.mTargetFuncArg);
+    if (typeof this.mTarget == "string")
+      return getNode(this.mTarget);
+
+    return this.mTarget;
+  }
+
+  function invokerChecker_targetSetter(aValue)
+  {
+    this.mTarget = aValue;
+    return this.mTarget;
+  }
+
+  this.__defineGetter__("targetDescr", invokerChecker_targetDescrGetter);
+
+  function invokerChecker_targetDescrGetter()
+  {
+    if (typeof this.mTarget == "function")
+      return this.mTarget.name + ", arg: " + this.mTargetFuncArg;
+
+    return prettyName(this.mTarget);
+  }
+
+  this.mTarget = aTargetOrFunc;
+  this.mTargetFuncArg = aTargetFuncArg;
+}
+
+/**
+ * event checker that forces preceeding async events to happen before this
+ * checker.
+ */
+function orderChecker()
+{
+  // XXX it doesn't actually work to inherit from invokerChecker, but maybe we
+  // should fix that?
+  //  this.__proto__ = new invokerChecker(null, null, null, false);
+}
+
+/**
+ * Generic invoker checker for todo events.
+ */
+function todo_invokerChecker(aEventType, aTargetOrFunc, aTargetFuncArg)
+{
+  this.__proto__ = new invokerChecker(aEventType, aTargetOrFunc,
+                                      aTargetFuncArg, true);
+  this.todo = true;
+}
+
+/**
+ * Generic invoker checker for unexpected events.
+ */
+function unexpectedInvokerChecker(aEventType, aTargetOrFunc, aTargetFuncArg)
+{
+  this.__proto__ = new invokerChecker(aEventType, aTargetOrFunc,
+                                      aTargetFuncArg, true);
+
+  this.unexpected = true;
+}
+
+/**
+ * Common invoker checker for async events.
+ */
+function asyncInvokerChecker(aEventType, aTargetOrFunc, aTargetFuncArg)
+{
+  this.__proto__ = new invokerChecker(aEventType, aTargetOrFunc,
+                                      aTargetFuncArg, true);
+}
+
+function focusChecker(aTargetOrFunc, aTargetFuncArg)
+{
+  this.__proto__ = new invokerChecker(EVENT_FOCUS, aTargetOrFunc,
+                                      aTargetFuncArg, false);
+
+  this.unique = true; // focus event must be unique for invoker action
+
+  this.check = function focusChecker_check(aEvent)
+  {
+    testStates(aEvent.accessible, STATE_FOCUSED);
+  }
+}
+
+function nofocusChecker(aID)
+{
+  this.__proto__ = new focusChecker(aID);
+  this.unexpected = true;
+}
+
+/**
+ * Text inserted/removed events checker.
+ * @param aFromUser  [in, optional] kNotFromUserInput or kFromUserInput
+ */
+function textChangeChecker(aID, aStart, aEnd, aTextOrFunc, aIsInserted, aFromUser, aAsync)
+{
+  this.target = getNode(aID);
+  this.type = aIsInserted ? EVENT_TEXT_INSERTED : EVENT_TEXT_REMOVED;
+  this.startOffset = aStart;
+  this.endOffset = aEnd;
+  this.textOrFunc = aTextOrFunc;
+  this.async = aAsync;
+
+  this.match = function stextChangeChecker_match(aEvent)
+  {
+    if (!(aEvent instanceof nsIAccessibleTextChangeEvent) ||
+        aEvent.accessible !== getAccessible(this.target)) {
+      return false;
+    }
+
+    let tcEvent = aEvent.QueryInterface(nsIAccessibleTextChangeEvent);
+    let modifiedText = (typeof this.textOrFunc === "function") ?
+      this.textOrFunc() : this.textOrFunc;
+    return modifiedText === tcEvent.modifiedText;
+  };
+
+  this.check = function textChangeChecker_check(aEvent)
+  {
+    aEvent.QueryInterface(nsIAccessibleTextChangeEvent);
+
+    var modifiedText = (typeof this.textOrFunc == "function") ?
+      this.textOrFunc() : this.textOrFunc;
+    var modifiedTextLen =
+      (this.endOffset == -1) ? modifiedText.length : aEnd - aStart;
+
+    is(aEvent.start, this.startOffset,
+       "Wrong start offset for " + prettyName(aID));
+    is(aEvent.length, modifiedTextLen, "Wrong length for " + prettyName(aID));
+    var changeInfo = (aIsInserted ? "inserted" : "removed");
+    is(aEvent.isInserted, aIsInserted,
+       "Text was " + changeInfo + " for " + prettyName(aID));
+    is(aEvent.modifiedText, modifiedText,
+       "Wrong " + changeInfo + " text for " + prettyName(aID));
+    if (typeof aFromUser != "undefined")
+      is(aEvent.isFromUserInput, aFromUser,
+         "wrong value of isFromUserInput() for " + prettyName(aID));
+  }
+}
+
+/**
+ * Caret move events checker.
+ */
+function caretMoveChecker(aCaretOffset, aTargetOrFunc, aTargetFuncArg,
+                          aIsAsync)
+{
+  this.__proto__ = new invokerChecker(EVENT_TEXT_CARET_MOVED,
+                                      aTargetOrFunc, aTargetFuncArg, aIsAsync);
+
+  this.check = function caretMoveChecker_check(aEvent)
+  {
+    is(aEvent.QueryInterface(nsIAccessibleCaretMoveEvent).caretOffset,
+       aCaretOffset,
+       "Wrong caret offset for " + prettyName(aEvent.accessible));
+  }
+}
+
+function asyncCaretMoveChecker(aCaretOffset, aTargetOrFunc, aTargetFuncArg)
+{
+  this.__proto__ = new caretMoveChecker(aCaretOffset, aTargetOrFunc,
+                                        aTargetFuncArg, true);
+}
+
+/**
+ * Text selection change checker.
+ */
+function textSelectionChecker(aID, aStartOffset, aEndOffset)
+{
+  this.__proto__ = new invokerChecker(EVENT_TEXT_SELECTION_CHANGED, aID);
+
+  this.check = function textSelectionChecker_check(aEvent)
+  {
+    if (aStartOffset == aEndOffset) {
+      ok(true, "Collapsed selection triggered text selection change event.");
+    } else {
+      testTextGetSelection(aID, aStartOffset, aEndOffset, 0);
+    }
+  }
+}
+
+/**
+ * Object attribute changed checker
+ */
+function objAttrChangedChecker(aID, aAttr)
+{
+  this.__proto__ = new invokerChecker(EVENT_OBJECT_ATTRIBUTE_CHANGED, aID);
+
+  this.check = function objAttrChangedChecker_check(aEvent)
+  {
+    var event = null;
+    try {
+      var event = aEvent.QueryInterface(
+        nsIAccessibleObjectAttributeChangedEvent);
+    } catch (e) {
+      ok(false, "Object attribute changed event was expected");
+    }
+
+    if (!event) {
+      return;
+    }
+
+    is(event.changedAttribute.toString(), aAttr,
+      "Wrong attribute name of the object attribute changed event.");
+  };
+
+  this.match = function objAttrChangedChecker_match(aEvent)
+  {
+    if (aEvent instanceof nsIAccessibleObjectAttributeChangedEvent) {
+      var scEvent = aEvent.QueryInterface(
+        nsIAccessibleObjectAttributeChangedEvent);
+      return (aEvent.accessible == getAccessible(this.target)) &&
+        (scEvent.changedAttribute.toString() == aAttr);
+    }
+    return false;
+  };
+}
+
+/**
+ * State change checker.
+ */
+function stateChangeChecker(aState, aIsExtraState, aIsEnabled,
+                            aTargetOrFunc, aTargetFuncArg, aIsAsync,
+                            aSkipCurrentStateCheck)
+{
+  this.__proto__ = new invokerChecker(EVENT_STATE_CHANGE, aTargetOrFunc,
+                                      aTargetFuncArg, aIsAsync);
+
+  this.check = function stateChangeChecker_check(aEvent)
+  {
+    var event = null;
+    try {
+      var event = aEvent.QueryInterface(nsIAccessibleStateChangeEvent);
+    } catch (e) {
+      ok(false, "State change event was expected");
+    }
+
+    if (!event)
+      return;
+
+    is(event.isExtraState, aIsExtraState,
+       "Wrong extra state bit of the statechange event.");
+    isState(event.state, aState, aIsExtraState,
+            "Wrong state of the statechange event.");
+    is(event.isEnabled, aIsEnabled,
+      "Wrong state of statechange event state");
+
+    if (aSkipCurrentStateCheck) {
+      todo(false, "State checking was skipped!");
+      return;
+    }
+
+    var state = aIsEnabled ? (aIsExtraState ? 0 : aState) : 0;
+    var extraState = aIsEnabled ? (aIsExtraState ? aState : 0) : 0;
+    var unxpdState = aIsEnabled ? 0 : (aIsExtraState ? 0 : aState);
+    var unxpdExtraState = aIsEnabled ? 0 : (aIsExtraState ? aState : 0);
+    testStates(event.accessible, state, extraState, unxpdState, unxpdExtraState);
+  }
+
+  this.match = function stateChangeChecker_match(aEvent)
+  {
+    if (aEvent instanceof nsIAccessibleStateChangeEvent) {
+      var scEvent = aEvent.QueryInterface(nsIAccessibleStateChangeEvent);
+      return (aEvent.accessible == getAccessible(this.target)) &&
+        (scEvent.state == aState);
+    }
+    return false;
+  }
+}
+
+function asyncStateChangeChecker(aState, aIsExtraState, aIsEnabled,
+                                 aTargetOrFunc, aTargetFuncArg)
+{
+  this.__proto__ = new stateChangeChecker(aState, aIsExtraState, aIsEnabled,
+                                          aTargetOrFunc, aTargetFuncArg, true);
+}
+
+/**
+ * Expanded state change checker.
+ */
+function expandedStateChecker(aIsEnabled, aTargetOrFunc, aTargetFuncArg)
+{
+  this.__proto__ = new invokerChecker(EVENT_STATE_CHANGE, aTargetOrFunc,
+                                      aTargetFuncArg);
+
+  this.check = function expandedStateChecker_check(aEvent)
+  {
+    var event = null;
+    try {
+      var event = aEvent.QueryInterface(nsIAccessibleStateChangeEvent);
+    } catch (e) {
+      ok(false, "State change event was expected");
+    }
+
+    if (!event)
+      return;
+
+    is(event.state, STATE_EXPANDED, "Wrong state of the statechange event.");
+    is(event.isExtraState, false,
+       "Wrong extra state bit of the statechange event.");
+    is(event.isEnabled, aIsEnabled,
+      "Wrong state of statechange event state");
+
+    testStates(event.accessible,
+               (aIsEnabled ? STATE_EXPANDED : STATE_COLLAPSED));
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Event sequances (array of predefined checkers)
+
+/**
+ * Event seq for single selection change.
+ */
+function selChangeSeq(aUnselectedID, aSelectedID)
+{
+  if (!aUnselectedID) {
+    return [
+      new stateChangeChecker(STATE_SELECTED, false, true, aSelectedID),
+      new invokerChecker(EVENT_SELECTION, aSelectedID)
+    ];
+  }
+
+  // Return two possible scenarios: depending on widget type when selection is
+  // moved the the order of items that get selected and unselected may vary. 
+  return [
+    [
+      new stateChangeChecker(STATE_SELECTED, false, false, aUnselectedID),
+      new stateChangeChecker(STATE_SELECTED, false, true, aSelectedID),
+      new invokerChecker(EVENT_SELECTION, aSelectedID)
+    ],
+    [
+      new stateChangeChecker(STATE_SELECTED, false, true, aSelectedID),
+      new stateChangeChecker(STATE_SELECTED, false, false, aUnselectedID),
+      new invokerChecker(EVENT_SELECTION, aSelectedID)
+    ]
+  ];
+}
+
+/**
+ * Event seq for item removed form the selection.
+ */
+function selRemoveSeq(aUnselectedID)
+{
+  return [
+    new stateChangeChecker(STATE_SELECTED, false, false, aUnselectedID),
+    new invokerChecker(EVENT_SELECTION_REMOVE, aUnselectedID)
+  ];
+}
+
+/**
+ * Event seq for item added to the selection.
+ */
+function selAddSeq(aSelectedID)
+{
+  return [
+    new stateChangeChecker(STATE_SELECTED, false, true, aSelectedID),
+    new invokerChecker(EVENT_SELECTION_ADD, aSelectedID)
+  ];
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Private implementation details.
+////////////////////////////////////////////////////////////////////////////////
+
+
+////////////////////////////////////////////////////////////////////////////////
+// General
+
+var gA11yEventListeners = {};
+var gA11yEventApplicantsCount = 0;
+
+var gA11yEventObserver =
+{
+  observe: function observe(aSubject, aTopic, aData)
+  {
+    if (aTopic != "accessible-event")
+      return;
+
+    var event;
+    try {
+      event = aSubject.QueryInterface(nsIAccessibleEvent);
+    } catch (ex) {
+      // After a test is aborted (i.e. timed out by the harness), this exception is soon triggered.
+      // Remove the leftover observer, otherwise it "leaks" to all the following tests.
+      Services.obs.removeObserver(this, "accessible-event");
+      // Forward the exception, with added explanation.
+      throw "[accessible/events.js, gA11yEventObserver.observe] This is expected if a previous test has been aborted... Initial exception was: [ " + ex + " ]";
+    }
+    var listenersArray = gA11yEventListeners[event.eventType];
+
+    var eventFromDumpArea = false;
+    if (gLogger.isEnabled()) { // debug stuff
+      eventFromDumpArea = true;
+
+      var target = event.DOMNode;
+      var dumpElm = gA11yEventDumpID ?
+        document.getElementById(gA11yEventDumpID) : null;
+
+      if (dumpElm) {
+        var parent = target;
+        while (parent && parent != dumpElm)
+          parent = parent.parentNode;
+      }
+
+      if (!dumpElm || parent != dumpElm) {
+        var type = eventTypeToString(event.eventType);
+        var info = "Event type: " + type;
+
+        if (event instanceof nsIAccessibleStateChangeEvent) {
+          var stateStr = statesToString(event.isExtraState ? 0 : event.state,
+                                        event.isExtraState ? event.state : 0);
+          info += ", state: " + stateStr + ", is enabled: " + event.isEnabled;
+
+        } else if (event instanceof nsIAccessibleTextChangeEvent) {
+          info += ", start: " + event.start + ", length: " + event.length +
+            ", " + (event.isInserted ? "inserted" : "removed") +
+            " text: " + event.modifiedText;
+        }
+
+        info += ". Target: " + prettyName(event.accessible);
+
+        if (listenersArray)
+          info += ". Listeners count: " + listenersArray.length;
+
+        if (gLogger.hasFeature("parentchain:" + type)) {
+          info += "\nParent chain:\n";
+          var acc = event.accessible;
+          while (acc) {
+            info += "  " + prettyName(acc) + "\n";
+            acc = acc.parent;
+          }
+        }
+
+        eventFromDumpArea = false;
+        gLogger.log(info);
+      }
+    }
+
+    // Do not notify listeners if event is result of event log changes.
+    if (!listenersArray || eventFromDumpArea)
+      return;
+
+    for (var index = 0; index < listenersArray.length; index++)
+      listenersArray[index].handleEvent(event);
+  }
+};
+
+function listenA11yEvents(aStartToListen)
+{
+  if (aStartToListen) {
+    // Add observer when adding the first applicant only.
+    if (!(gA11yEventApplicantsCount++))
+      Services.obs.addObserver(gA11yEventObserver, "accessible-event", false);
+  } else {
+    // Remove observer when there are no more applicants only.
+    // '< 0' case should not happen, but just in case: removeObserver() will throw.
+    if (--gA11yEventApplicantsCount <= 0)
+      Services.obs.removeObserver(gA11yEventObserver, "accessible-event");
+  }
+}
+
+function addA11yEventListener(aEventType, aEventHandler)
+{
+  if (!(aEventType in gA11yEventListeners))
+    gA11yEventListeners[aEventType] = new Array();
+
+  var listenersArray = gA11yEventListeners[aEventType];
+  var index = listenersArray.indexOf(aEventHandler);
+  if (index == -1)
+    listenersArray.push(aEventHandler);
+}
+
+function removeA11yEventListener(aEventType, aEventHandler)
+{
+  var listenersArray = gA11yEventListeners[aEventType];
+  if (!listenersArray)
+    return false;
+
+  var index = listenersArray.indexOf(aEventHandler);
+  if (index == -1)
+    return false;
+
+  listenersArray.splice(index, 1);
+  
+  if (!listenersArray.length) {
+    gA11yEventListeners[aEventType] = null;
+    delete gA11yEventListeners[aEventType];
+  }
+
+  return true;
+}
+
+/**
+ * Used to dump debug information.
+ */
+var gLogger =
+{
+  /**
+   * Return true if dump is enabled.
+   */
+  isEnabled: function debugOutput_isEnabled()
+  {
+    return gA11yEventDumpID || gA11yEventDumpToConsole ||
+      gA11yEventDumpToAppConsole;
+  },
+
+  /**
+   * Dump information into DOM and console if applicable.
+   */
+  log: function logger_log(aMsg)
+  {
+    this.logToConsole(aMsg);
+    this.logToAppConsole(aMsg);
+    this.logToDOM(aMsg);
+  },
+
+  /**
+   * Log message to DOM.
+   *
+   * @param aMsg          [in] the primary message
+   * @param aHasIndent    [in, optional] if specified the message has an indent
+   * @param aPreEmphText  [in, optional] the text is colored and appended prior
+   *                        primary message
+   */
+  logToDOM: function logger_logToDOM(aMsg, aHasIndent, aPreEmphText)
+  {
+    if (gA11yEventDumpID == "")
+      return;
+
+    var dumpElm = document.getElementById(gA11yEventDumpID);
+    if (!dumpElm) {
+      ok(false,
+         "No dump element '" + gA11yEventDumpID + "' within the document!");
+      return;
+    }
+
+    var containerTagName = document instanceof nsIDOMHTMLDocument ?
+      "div" : "description";
+
+    var container = document.createElement(containerTagName);
+    if (aHasIndent)
+      container.setAttribute("style", "padding-left: 10px;");
+
+    if (aPreEmphText) {
+      var inlineTagName = document instanceof nsIDOMHTMLDocument ?
+        "span" : "description";
+      var emphElm = document.createElement(inlineTagName);
+      emphElm.setAttribute("style", "color: blue;");
+      emphElm.textContent = aPreEmphText;
+
+      container.appendChild(emphElm);
+    }
+
+    var textNode = document.createTextNode(aMsg);
+    container.appendChild(textNode);
+
+    dumpElm.appendChild(container);
+  },
+
+  /**
+   * Log message to console.
+   */
+  logToConsole: function logger_logToConsole(aMsg)
+  {
+    if (gA11yEventDumpToConsole)
+      dump("\n" + aMsg + "\n");
+  },
+
+  /**
+   * Log message to error console.
+   */
+  logToAppConsole: function logger_logToAppConsole(aMsg)
+  {
+    if (gA11yEventDumpToAppConsole)
+      Services.console.logStringMessage("events: " + aMsg);
+  },
+
+  /**
+   * Return true if logging feature is enabled.
+   */
+  hasFeature: function logger_hasFeature(aFeature)
+  {
+    var startIdx = gA11yEventDumpFeature.indexOf(aFeature);
+    if (startIdx == - 1)
+      return false;
+
+    var endIdx = startIdx + aFeature.length;
+    return endIdx == gA11yEventDumpFeature.length ||
+      gA11yEventDumpFeature[endIdx] == ";";
+  }
+};
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Sequence
+
+/**
+ * Base class of sequence item.
+ */
+function sequenceItem(aProcessor, aEventType, aTarget, aItemID)
+{
+  // private
+  
+  this.startProcess = function sequenceItem_startProcess()
+  {
+    this.queue.invoke();
+  }
+  
+  var item = this;
+  
+  this.queue = new eventQueue();
+  this.queue.onFinish = function()
+  {
+    aProcessor.onProcessed();
+    return DO_NOT_FINISH_TEST;
+  }
+  
+  var invoker = {
+    invoke: function invoker_invoke() {
+      return aProcessor.process();
+    },
+    getID: function invoker_getID()
+    {
+      return aItemID;
+    },
+    eventSeq: [ new invokerChecker(aEventType, aTarget) ]
+  };
+  
+  this.queue.push(invoker);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Event queue invokers
+
+/**
+ * Invoker base class for prepare an action.
+ */
+function synthAction(aNodeOrID, aEventsObj)
+{
+  this.DOMNode = getNode(aNodeOrID);
+
+  if (aEventsObj) {
+    var scenarios = null;
+    if (aEventsObj instanceof Array) {
+      if (aEventsObj[0] instanceof Array)
+        scenarios = aEventsObj; // scenarios
+      else
+        scenarios = [ aEventsObj ]; // event sequance
+    } else {
+      scenarios = [ [ aEventsObj ] ]; // a single checker object
+    }
+
+    for (var i = 0; i < scenarios.length; i++)
+      defineScenario(this, scenarios[i]);
+  }
+
+  this.getID = function synthAction_getID()
+    { return prettyName(aNodeOrID) + " action"; }
+}