Add third_party/google-input-tools: Take 2

third_party/google_input_tools/third_party/closure_library/closure/goog/ui/container.js

Index: third_party/google_input_tools/third_party/closure_library/closure/goog/ui/container.js
diff --git a/third_party/google_input_tools/third_party/closure_library/closure/goog/ui/container.js b/third_party/google_input_tools/third_party/closure_library/closure/goog/ui/container.js
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index 0000000000000000000000000000000000000000..b33947b292fbd5b03ff2f26b66fe2b45342f5e65
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@@ -0,0 +1,1324 @@
+// Copyright 2007 The Closure Library Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS-IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/**
+ * @fileoverview Base class for containers that host {@link goog.ui.Control}s,
+ * such as menus and toolbars.  Provides default keyboard and mouse event
+ * handling and child management, based on a generalized version of
+ * {@link goog.ui.Menu}.
+ *
+ * @author attila@google.com (Attila Bodis)
+ * @see ../demos/container.html
+ */
+// TODO(attila):  Fix code/logic duplication between this and goog.ui.Control.
+// TODO(attila):  Maybe pull common stuff all the way up into Component...?
+
+goog.provide('goog.ui.Container');
+goog.provide('goog.ui.Container.EventType');
+goog.provide('goog.ui.Container.Orientation');
+
+goog.require('goog.a11y.aria');
+goog.require('goog.a11y.aria.State');
+goog.require('goog.asserts');
+goog.require('goog.dom');
+goog.require('goog.events.EventType');
+goog.require('goog.events.KeyCodes');
+goog.require('goog.events.KeyHandler');
+goog.require('goog.object');
+goog.require('goog.style');
+goog.require('goog.ui.Component');
+goog.require('goog.ui.ContainerRenderer');
+goog.require('goog.ui.Control');
+
+
+
+/**
+ * Base class for containers.  Extends {@link goog.ui.Component} by adding
+ * the following:
+ *  <ul>
+ *    <li>a {@link goog.events.KeyHandler}, to simplify keyboard handling,
+ *    <li>a pluggable <em>renderer</em> framework, to simplify the creation of
+ *        containers without the need to subclass this class,
+ *    <li>methods to manage child controls hosted in the container,
+ *    <li>default mouse and keyboard event handling methods.
+ *  </ul>
+ * @param {?goog.ui.Container.Orientation=} opt_orientation Container
+ *     orientation; defaults to {@code VERTICAL}.
+ * @param {goog.ui.ContainerRenderer=} opt_renderer Renderer used to render or
+ *     decorate the container; defaults to {@link goog.ui.ContainerRenderer}.
+ * @param {goog.dom.DomHelper=} opt_domHelper DOM helper, used for document
+ *     interaction.
+ * @extends {goog.ui.Component}
+ * @constructor
+ */
+goog.ui.Container = function(opt_orientation, opt_renderer, opt_domHelper) {
+  goog.ui.Component.call(this, opt_domHelper);
+  this.renderer_ = opt_renderer || goog.ui.ContainerRenderer.getInstance();
+  this.orientation_ = opt_orientation || this.renderer_.getDefaultOrientation();
+};
+goog.inherits(goog.ui.Container, goog.ui.Component);
+goog.tagUnsealableClass(goog.ui.Container);
+
+
+/**
+ * Container-specific events.
+ * @enum {string}
+ */
+goog.ui.Container.EventType = {
+  /**
+   * Dispatched after a goog.ui.Container becomes visible. Non-cancellable.
+   * NOTE(user): This event really shouldn't exist, because the
+   * goog.ui.Component.EventType.SHOW event should behave like this one. But the
+   * SHOW event for containers has been behaving as other components'
+   * BEFORE_SHOW event for a long time, and too much code relies on that old
+   * behavior to fix it now.
+   */
+  AFTER_SHOW: 'aftershow',
+
+  /**
+   * Dispatched after a goog.ui.Container becomes invisible. Non-cancellable.
+   */
+  AFTER_HIDE: 'afterhide'
+};
+
+
+/**
+ * Container orientation constants.
+ * @enum {string}
+ */
+goog.ui.Container.Orientation = {
+  HORIZONTAL: 'horizontal',
+  VERTICAL: 'vertical'
+};
+
+
+/**
+ * Allows an alternative element to be set to receive key events, otherwise
+ * defers to the renderer's element choice.
+ * @type {Element|undefined}
+ * @private
+ */
+goog.ui.Container.prototype.keyEventTarget_ = null;
+
+
+/**
+ * Keyboard event handler.
+ * @type {goog.events.KeyHandler?}
+ * @private
+ */
+goog.ui.Container.prototype.keyHandler_ = null;
+
+
+/**
+ * Renderer for the container.  Defaults to {@link goog.ui.ContainerRenderer}.
+ * @type {goog.ui.ContainerRenderer?}
+ * @private
+ */
+goog.ui.Container.prototype.renderer_ = null;
+
+
+/**
+ * Container orientation; determines layout and default keyboard navigation.
+ * @type {?goog.ui.Container.Orientation}
+ * @private
+ */
+goog.ui.Container.prototype.orientation_ = null;
+
+
+/**
+ * Whether the container is set to be visible.  Defaults to true.
+ * @type {boolean}
+ * @private
+ */
+goog.ui.Container.prototype.visible_ = true;
+
+
+/**
+ * Whether the container is enabled and reacting to keyboard and mouse events.
+ * Defaults to true.
+ * @type {boolean}
+ * @private
+ */
+goog.ui.Container.prototype.enabled_ = true;
+
+
+/**
+ * Whether the container supports keyboard focus.  Defaults to true.  Focusable
+ * containers have a {@code tabIndex} and can be navigated to via the keyboard.
+ * @type {boolean}
+ * @private
+ */
+goog.ui.Container.prototype.focusable_ = true;
+
+
+/**
+ * The 0-based index of the currently highlighted control in the container
+ * (-1 if none).
+ * @type {number}
+ * @private
+ */
+goog.ui.Container.prototype.highlightedIndex_ = -1;
+
+
+/**
+ * The currently open (expanded) control in the container (null if none).
+ * @type {goog.ui.Control?}
+ * @private
+ */
+goog.ui.Container.prototype.openItem_ = null;
+
+
+/**
+ * Whether the mouse button is held down.  Defaults to false.  This flag is set
+ * when the user mouses down over the container, and remains set until they
+ * release the mouse button.
+ * @type {boolean}
+ * @private
+ */
+goog.ui.Container.prototype.mouseButtonPressed_ = false;
+
+
+/**
+ * Whether focus of child components should be allowed.  Only effective if
+ * focusable_ is set to false.
+ * @type {boolean}
+ * @private
+ */
+goog.ui.Container.prototype.allowFocusableChildren_ = false;
+
+
+/**
+ * Whether highlighting a child component should also open it.
+ * @type {boolean}
+ * @private
+ */
+goog.ui.Container.prototype.openFollowsHighlight_ = true;
+
+
+/**
+ * Map of DOM IDs to child controls.  Each key is the DOM ID of a child
+ * control's root element; each value is a reference to the child control
+ * itself.  Used for looking up the child control corresponding to a DOM
+ * node in O(1) time.
+ * @type {Object}
+ * @private
+ */
+goog.ui.Container.prototype.childElementIdMap_ = null;
+
+
+// Event handler and renderer management.
+
+
+/**
+ * Returns the DOM element on which the container is listening for keyboard
+ * events (null if none).
+ * @return {Element} Element on which the container is listening for key
+ *     events.
+ */
+goog.ui.Container.prototype.getKeyEventTarget = function() {
+  // Delegate to renderer, unless we've set an explicit target.
+  return this.keyEventTarget_ || this.renderer_.getKeyEventTarget(this);
+};
+
+
+/**
+ * Attaches an element on which to listen for key events.
+ * @param {Element|undefined} element The element to attach, or null/undefined
+ *     to attach to the default element.
+ */
+goog.ui.Container.prototype.setKeyEventTarget = function(element) {
+  if (this.focusable_) {
+    var oldTarget = this.getKeyEventTarget();
+    var inDocument = this.isInDocument();
+
+    this.keyEventTarget_ = element;
+    var newTarget = this.getKeyEventTarget();
+
+    if (inDocument) {
+      // Unlisten for events on the old key target.  Requires us to reset
+      // key target state temporarily.
+      this.keyEventTarget_ = oldTarget;
+      this.enableFocusHandling_(false);
+      this.keyEventTarget_ = element;
+
+      // Listen for events on the new key target.
+      this.getKeyHandler().attach(newTarget);
+      this.enableFocusHandling_(true);
+    }
+  } else {
+    throw Error('Can\'t set key event target for container ' +
+        'that doesn\'t support keyboard focus!');
+  }
+};
+
+
+/**
+ * Returns the keyboard event handler for this container, lazily created the
+ * first time this method is called.  The keyboard event handler listens for
+ * keyboard events on the container's key event target, as determined by its
+ * renderer.
+ * @return {!goog.events.KeyHandler} Keyboard event handler for this container.
+ */
+goog.ui.Container.prototype.getKeyHandler = function() {
+  return this.keyHandler_ ||
+      (this.keyHandler_ = new goog.events.KeyHandler(this.getKeyEventTarget()));
+};
+
+
+/**
+ * Returns the renderer used by this container to render itself or to decorate
+ * an existing element.
+ * @return {goog.ui.ContainerRenderer} Renderer used by the container.
+ */
+goog.ui.Container.prototype.getRenderer = function() {
+  return this.renderer_;
+};
+
+
+/**
+ * Registers the given renderer with the container.  Changing renderers after
+ * the container has already been rendered or decorated is an error.
+ * @param {goog.ui.ContainerRenderer} renderer Renderer used by the container.
+ */
+goog.ui.Container.prototype.setRenderer = function(renderer) {
+  if (this.getElement()) {
+    // Too late.
+    throw Error(goog.ui.Component.Error.ALREADY_RENDERED);
+  }
+
+  this.renderer_ = renderer;
+};
+
+
+// Standard goog.ui.Component implementation.
+
+
+/**
+ * Creates the container's DOM.
+ * @override
+ */
+goog.ui.Container.prototype.createDom = function() {
+  // Delegate to renderer.
+  this.setElementInternal(this.renderer_.createDom(this));
+};
+
+
+/**
+ * Returns the DOM element into which child components are to be rendered,
+ * or null if the container itself hasn't been rendered yet.  Overrides
+ * {@link goog.ui.Component#getContentElement} by delegating to the renderer.
+ * @return {Element} Element to contain child elements (null if none).
+ * @override
+ */
+goog.ui.Container.prototype.getContentElement = function() {
+  // Delegate to renderer.
+  return this.renderer_.getContentElement(this.getElement());
+};
+
+
+/**
+ * Returns true if the given element can be decorated by this container.
+ * Overrides {@link goog.ui.Component#canDecorate}.
+ * @param {Element} element Element to decorate.
+ * @return {boolean} True iff the element can be decorated.
+ * @override
+ */
+goog.ui.Container.prototype.canDecorate = function(element) {
+  // Delegate to renderer.
+  return this.renderer_.canDecorate(element);
+};
+
+
+/**
+ * Decorates the given element with this container. Overrides {@link
+ * goog.ui.Component#decorateInternal}.  Considered protected.
+ * @param {Element} element Element to decorate.
+ * @override
+ */
+goog.ui.Container.prototype.decorateInternal = function(element) {
+  // Delegate to renderer.
+  this.setElementInternal(this.renderer_.decorate(this, element));
+  // Check whether the decorated element is explicitly styled to be invisible.
+  if (element.style.display == 'none') {
+    this.visible_ = false;
+  }
+};
+
+
+/**
+ * Configures the container after its DOM has been rendered, and sets up event
+ * handling.  Overrides {@link goog.ui.Component#enterDocument}.
+ * @override
+ */
+goog.ui.Container.prototype.enterDocument = function() {
+  goog.ui.Container.superClass_.enterDocument.call(this);
+
+  this.forEachChild(function(child) {
+    if (child.isInDocument()) {
+      this.registerChildId_(child);
+    }
+  }, this);
+
+  var elem = this.getElement();
+
+  // Call the renderer's initializeDom method to initialize the container's DOM.
+  this.renderer_.initializeDom(this);
+
+  // Initialize visibility (opt_force = true, so we don't dispatch events).
+  this.setVisible(this.visible_, true);
+
+  // Handle events dispatched by child controls.
+  this.getHandler().
+      listen(this, goog.ui.Component.EventType.ENTER,
+          this.handleEnterItem).
+      listen(this, goog.ui.Component.EventType.HIGHLIGHT,
+          this.handleHighlightItem).
+      listen(this, goog.ui.Component.EventType.UNHIGHLIGHT,
+          this.handleUnHighlightItem).
+      listen(this, goog.ui.Component.EventType.OPEN, this.handleOpenItem).
+      listen(this, goog.ui.Component.EventType.CLOSE, this.handleCloseItem).
+
+      // Handle mouse events.
+      listen(elem, goog.events.EventType.MOUSEDOWN, this.handleMouseDown).
+      listen(goog.dom.getOwnerDocument(elem), goog.events.EventType.MOUSEUP,
+          this.handleDocumentMouseUp).
+
+      // Handle mouse events on behalf of controls in the container.
+      listen(elem, [
+        goog.events.EventType.MOUSEDOWN,
+        goog.events.EventType.MOUSEUP,
+        goog.events.EventType.MOUSEOVER,
+        goog.events.EventType.MOUSEOUT,
+        goog.events.EventType.CONTEXTMENU
+      ], this.handleChildMouseEvents);
+
+  // If the container is focusable, set up keyboard event handling.
+  if (this.isFocusable()) {
+    this.enableFocusHandling_(true);
+  }
+};
+
+
+/**
+ * Sets up listening for events applicable to focusable containers.
+ * @param {boolean} enable Whether to enable or disable focus handling.
+ * @private
+ */
+goog.ui.Container.prototype.enableFocusHandling_ = function(enable) {
+  var handler = this.getHandler();
+  var keyTarget = this.getKeyEventTarget();
+  if (enable) {
+    handler.
+        listen(keyTarget, goog.events.EventType.FOCUS, this.handleFocus).
+        listen(keyTarget, goog.events.EventType.BLUR, this.handleBlur).
+        listen(this.getKeyHandler(), goog.events.KeyHandler.EventType.KEY,
+            this.handleKeyEvent);
+  } else {
+    handler.
+        unlisten(keyTarget, goog.events.EventType.FOCUS, this.handleFocus).
+        unlisten(keyTarget, goog.events.EventType.BLUR, this.handleBlur).
+        unlisten(this.getKeyHandler(), goog.events.KeyHandler.EventType.KEY,
+            this.handleKeyEvent);
+  }
+};
+
+
+/**
+ * Cleans up the container before its DOM is removed from the document, and
+ * removes event handlers.  Overrides {@link goog.ui.Component#exitDocument}.
+ * @override
+ */
+goog.ui.Container.prototype.exitDocument = function() {
+  // {@link #setHighlightedIndex} has to be called before
+  // {@link goog.ui.Component#exitDocument}, otherwise it has no effect.
+  this.setHighlightedIndex(-1);
+
+  if (this.openItem_) {
+    this.openItem_.setOpen(false);
+  }
+
+  this.mouseButtonPressed_ = false;
+
+  goog.ui.Container.superClass_.exitDocument.call(this);
+};
+
+
+/** @override */
+goog.ui.Container.prototype.disposeInternal = function() {
+  goog.ui.Container.superClass_.disposeInternal.call(this);
+
+  if (this.keyHandler_) {
+    this.keyHandler_.dispose();
+    this.keyHandler_ = null;
+  }
+
+  this.keyEventTarget_ = null;
+  this.childElementIdMap_ = null;
+  this.openItem_ = null;
+  this.renderer_ = null;
+};
+
+
+// Default event handlers.
+
+
+/**
+ * Handles ENTER events raised by child controls when they are navigated to.
+ * @param {goog.events.Event} e ENTER event to handle.
+ * @return {boolean} Whether to prevent handleMouseOver from handling
+ *    the event.
+ */
+goog.ui.Container.prototype.handleEnterItem = function(e) {
+  // Allow the Control to highlight itself.
+  return true;
+};
+
+
+/**
+ * Handles HIGHLIGHT events dispatched by items in the container when
+ * they are highlighted.
+ * @param {goog.events.Event} e Highlight event to handle.
+ */
+goog.ui.Container.prototype.handleHighlightItem = function(e) {
+  var index = this.indexOfChild(/** @type {goog.ui.Control} */ (e.target));
+  if (index > -1 && index != this.highlightedIndex_) {
+    var item = this.getHighlighted();
+    if (item) {
+      // Un-highlight previously highlighted item.
+      item.setHighlighted(false);
+    }
+
+    this.highlightedIndex_ = index;
+    item = this.getHighlighted();
+
+    if (this.isMouseButtonPressed()) {
+      // Activate item when mouse button is pressed, to allow MacOS-style
+      // dragging to choose menu items.  Although this should only truly
+      // happen if the highlight is due to mouse movements, there is little
+      // harm in doing it for keyboard or programmatic highlights.
+      item.setActive(true);
+    }
+
+    // Update open item if open item needs follow highlight.
+    if (this.openFollowsHighlight_ &&
+        this.openItem_ && item != this.openItem_) {
+      if (item.isSupportedState(goog.ui.Component.State.OPENED)) {
+        item.setOpen(true);
+      } else {
+        this.openItem_.setOpen(false);
+      }
+    }
+  }
+
+  var element = this.getElement();
+  goog.asserts.assert(element,
+      'The DOM element for the container cannot be null.');
+  if (e.target.getElement() != null) {
+    goog.a11y.aria.setState(element,
+        goog.a11y.aria.State.ACTIVEDESCENDANT,
+        e.target.getElement().id);
+  }
+};
+
+
+/**
+ * Handles UNHIGHLIGHT events dispatched by items in the container when
+ * they are unhighlighted.
+ * @param {goog.events.Event} e Unhighlight event to handle.
+ */
+goog.ui.Container.prototype.handleUnHighlightItem = function(e) {
+  if (e.target == this.getHighlighted()) {
+    this.highlightedIndex_ = -1;
+  }
+  var element = this.getElement();
+  goog.asserts.assert(element,
+      'The DOM element for the container cannot be null.');
+  // Setting certain ARIA attributes to empty strings is problematic.
+  // Just remove the attribute instead.
+  goog.a11y.aria.removeState(element, goog.a11y.aria.State.ACTIVEDESCENDANT);
+};
+
+
+/**
+ * Handles OPEN events dispatched by items in the container when they are
+ * opened.
+ * @param {goog.events.Event} e Open event to handle.
+ */
+goog.ui.Container.prototype.handleOpenItem = function(e) {
+  var item = /** @type {goog.ui.Control} */ (e.target);
+  if (item && item != this.openItem_ && item.getParent() == this) {
+    if (this.openItem_) {
+      this.openItem_.setOpen(false);
+    }
+    this.openItem_ = item;
+  }
+};
+
+
+/**
+ * Handles CLOSE events dispatched by items in the container when they are
+ * closed.
+ * @param {goog.events.Event} e Close event to handle.
+ */
+goog.ui.Container.prototype.handleCloseItem = function(e) {
+  if (e.target == this.openItem_) {
+    this.openItem_ = null;
+  }
+};
+
+
+/**
+ * Handles mousedown events over the container.  The default implementation
+ * sets the "mouse button pressed" flag and, if the container is focusable,
+ * grabs keyboard focus.
+ * @param {goog.events.BrowserEvent} e Mousedown event to handle.
+ */
+goog.ui.Container.prototype.handleMouseDown = function(e) {
+  if (this.enabled_) {
+    this.setMouseButtonPressed(true);
+  }
+
+  var keyTarget = this.getKeyEventTarget();
+  if (keyTarget && goog.dom.isFocusableTabIndex(keyTarget)) {
+    // The container is configured to receive keyboard focus.
+    keyTarget.focus();
+  } else {
+    // The control isn't configured to receive keyboard focus; prevent it
+    // from stealing focus or destroying the selection.
+    e.preventDefault();
+  }
+};
+
+
+/**
+ * Handles mouseup events over the document.  The default implementation
+ * clears the "mouse button pressed" flag.
+ * @param {goog.events.BrowserEvent} e Mouseup event to handle.
+ */
+goog.ui.Container.prototype.handleDocumentMouseUp = function(e) {
+  this.setMouseButtonPressed(false);
+};
+
+
+/**
+ * Handles mouse events originating from nodes belonging to the controls hosted
+ * in the container.  Locates the child control based on the DOM node that
+ * dispatched the event, and forwards the event to the control for handling.
+ * @param {goog.events.BrowserEvent} e Mouse event to handle.
+ */
+goog.ui.Container.prototype.handleChildMouseEvents = function(e) {
+  var control = this.getOwnerControl(/** @type {Node} */ (e.target));
+  if (control) {
+    // Child control identified; forward the event.
+    switch (e.type) {
+      case goog.events.EventType.MOUSEDOWN:
+        control.handleMouseDown(e);
+        break;
+      case goog.events.EventType.MOUSEUP:
+        control.handleMouseUp(e);
+        break;
+      case goog.events.EventType.MOUSEOVER:
+        control.handleMouseOver(e);
+        break;
+      case goog.events.EventType.MOUSEOUT:
+        control.handleMouseOut(e);
+        break;
+      case goog.events.EventType.CONTEXTMENU:
+        control.handleContextMenu(e);
+        break;
+    }
+  }
+};
+
+
+/**
+ * Returns the child control that owns the given DOM node, or null if no such
+ * control is found.
+ * @param {Node} node DOM node whose owner is to be returned.
+ * @return {goog.ui.Control?} Control hosted in the container to which the node
+ *     belongs (if found).
+ * @protected
+ */
+goog.ui.Container.prototype.getOwnerControl = function(node) {
+  // Ensure that this container actually has child controls before
+  // looking up the owner.
+  if (this.childElementIdMap_) {
+    var elem = this.getElement();
+    // See http://b/2964418 . IE9 appears to evaluate '!=' incorrectly, so
+    // using '!==' instead.
+    // TODO(user): Possibly revert this change if/when IE9 fixes the issue.
+    while (node && node !== elem) {
+      var id = node.id;
+      if (id in this.childElementIdMap_) {
+        return this.childElementIdMap_[id];
+      }
+      node = node.parentNode;
+    }
+  }
+  return null;
+};
+
+
+/**
+ * Handles focus events raised when the container's key event target receives
+ * keyboard focus.
+ * @param {goog.events.BrowserEvent} e Focus event to handle.
+ */
+goog.ui.Container.prototype.handleFocus = function(e) {
+  // No-op in the base class.
+};
+
+
+/**
+ * Handles blur events raised when the container's key event target loses
+ * keyboard focus.  The default implementation clears the highlight index.
+ * @param {goog.events.BrowserEvent} e Blur event to handle.
+ */
+goog.ui.Container.prototype.handleBlur = function(e) {
+  this.setHighlightedIndex(-1);
+  this.setMouseButtonPressed(false);
+  // If the container loses focus, and one of its children is open, close it.
+  if (this.openItem_) {
+    this.openItem_.setOpen(false);
+  }
+};
+
+
+/**
+ * Attempts to handle a keyboard event, if the control is enabled, by calling
+ * {@link handleKeyEventInternal}.  Considered protected; should only be used
+ * within this package and by subclasses.
+ * @param {goog.events.KeyEvent} e Key event to handle.
+ * @return {boolean} Whether the key event was handled.
+ */
+goog.ui.Container.prototype.handleKeyEvent = function(e) {
+  if (this.isEnabled() && this.isVisible() &&
+      (this.getChildCount() != 0 || this.keyEventTarget_) &&
+      this.handleKeyEventInternal(e)) {
+    e.preventDefault();
+    e.stopPropagation();
+    return true;
+  }
+  return false;
+};
+
+
+/**
+ * Attempts to handle a keyboard event; returns true if the event was handled,
+ * false otherwise.  If the container is enabled, and a child is highlighted,
+ * calls the child control's {@code handleKeyEvent} method to give the control
+ * a chance to handle the event first.
+ * @param {goog.events.KeyEvent} e Key event to handle.
+ * @return {boolean} Whether the event was handled by the container (or one of
+ *     its children).
+ */
+goog.ui.Container.prototype.handleKeyEventInternal = function(e) {
+  // Give the highlighted control the chance to handle the key event.
+  var highlighted = this.getHighlighted();
+  if (highlighted && typeof highlighted.handleKeyEvent == 'function' &&
+      highlighted.handleKeyEvent(e)) {
+    return true;
+  }
+
+  // Give the open control the chance to handle the key event.
+  if (this.openItem_ && this.openItem_ != highlighted &&
+      typeof this.openItem_.handleKeyEvent == 'function' &&
+      this.openItem_.handleKeyEvent(e)) {
+    return true;
+  }
+
+  // Do not handle the key event if any modifier key is pressed.
+  if (e.shiftKey || e.ctrlKey || e.metaKey || e.altKey) {
+    return false;
+  }
+
+  // Either nothing is highlighted, or the highlighted control didn't handle
+  // the key event, so attempt to handle it here.
+  switch (e.keyCode) {
+    case goog.events.KeyCodes.ESC:
+      if (this.isFocusable()) {
+        this.getKeyEventTarget().blur();
+      } else {
+        return false;
+      }
+      break;
+
+    case goog.events.KeyCodes.HOME:
+      this.highlightFirst();
+      break;
+
+    case goog.events.KeyCodes.END:
+      this.highlightLast();
+      break;
+
+    case goog.events.KeyCodes.UP:
+      if (this.orientation_ == goog.ui.Container.Orientation.VERTICAL) {
+        this.highlightPrevious();
+      } else {
+        return false;
+      }
+      break;
+
+    case goog.events.KeyCodes.LEFT:
+      if (this.orientation_ == goog.ui.Container.Orientation.HORIZONTAL) {
+        if (this.isRightToLeft()) {
+          this.highlightNext();
+        } else {
+          this.highlightPrevious();
+        }
+      } else {
+        return false;
+      }
+      break;
+
+    case goog.events.KeyCodes.DOWN:
+      if (this.orientation_ == goog.ui.Container.Orientation.VERTICAL) {
+        this.highlightNext();
+      } else {
+        return false;
+      }
+      break;
+
+    case goog.events.KeyCodes.RIGHT:
+      if (this.orientation_ == goog.ui.Container.Orientation.HORIZONTAL) {
+        if (this.isRightToLeft()) {
+          this.highlightPrevious();
+        } else {
+          this.highlightNext();
+        }
+      } else {
+        return false;
+      }
+      break;
+
+    default:
+      return false;
+  }
+
+  return true;
+};
+
+
+// Child component management.
+
+
+/**
+ * Creates a DOM ID for the child control and registers it to an internal
+ * hash table to be able to find it fast by id.
+ * @param {goog.ui.Component} child The child control. Its root element has
+ *     to be created yet.
+ * @private
+ */
+goog.ui.Container.prototype.registerChildId_ = function(child) {
+  // Map the DOM ID of the control's root element to the control itself.
+  var childElem = child.getElement();
+
+  // If the control's root element doesn't have a DOM ID assign one.
+  var id = childElem.id || (childElem.id = child.getId());
+
+  // Lazily create the child element ID map on first use.
+  if (!this.childElementIdMap_) {
+    this.childElementIdMap_ = {};
+  }
+  this.childElementIdMap_[id] = child;
+};
+
+
+/**
+ * Adds the specified control as the last child of this container.  See
+ * {@link goog.ui.Container#addChildAt} for detailed semantics.
+ * @param {goog.ui.Component} child The new child control.
+ * @param {boolean=} opt_render Whether the new child should be rendered
+ *     immediately after being added (defaults to false).
+ * @override
+ */
+goog.ui.Container.prototype.addChild = function(child, opt_render) {
+  goog.asserts.assertInstanceof(child, goog.ui.Control,
+      'The child of a container must be a control');
+  goog.ui.Container.superClass_.addChild.call(this, child, opt_render);
+};
+
+
+/**
+ * Overrides {@link goog.ui.Container#getChild} to make it clear that it
+ * only returns {@link goog.ui.Control}s.
+ * @param {string} id Child component ID.
+ * @return {goog.ui.Control} The child with the given ID; null if none.
+ * @override
+ */
+goog.ui.Container.prototype.getChild;
+
+
+/**
+ * Overrides {@link goog.ui.Container#getChildAt} to make it clear that it
+ * only returns {@link goog.ui.Control}s.
+ * @param {number} index 0-based index.
+ * @return {goog.ui.Control} The child with the given ID; null if none.
+ * @override
+ */
+goog.ui.Container.prototype.getChildAt;
+
+
+/**
+ * Adds the control as a child of this container at the given 0-based index.
+ * Overrides {@link goog.ui.Component#addChildAt} by also updating the
+ * container's highlight index.  Since {@link goog.ui.Component#addChild} uses
+ * {@link #addChildAt} internally, we only need to override this method.
+ * @param {goog.ui.Component} control New child.
+ * @param {number} index Index at which the new child is to be added.
+ * @param {boolean=} opt_render Whether the new child should be rendered
+ *     immediately after being added (defaults to false).
+ * @override
+ */
+goog.ui.Container.prototype.addChildAt = function(control, index, opt_render) {
+  // Make sure the child control dispatches HIGHLIGHT, UNHIGHLIGHT, OPEN, and
+  // CLOSE events, and that it doesn't steal keyboard focus.
+  control.setDispatchTransitionEvents(goog.ui.Component.State.HOVER, true);
+  control.setDispatchTransitionEvents(goog.ui.Component.State.OPENED, true);
+  if (this.isFocusable() || !this.isFocusableChildrenAllowed()) {
+    control.setSupportedState(goog.ui.Component.State.FOCUSED, false);
+  }
+
+  // Disable mouse event handling by child controls.
+  control.setHandleMouseEvents(false);
+
+  // Let the superclass implementation do the work.
+  goog.ui.Container.superClass_.addChildAt.call(this, control, index,
+      opt_render);
+
+  if (control.isInDocument() && this.isInDocument()) {
+    this.registerChildId_(control);
+  }
+
+  // Update the highlight index, if needed.
+  if (index <= this.highlightedIndex_) {
+    this.highlightedIndex_++;
+  }
+};
+
+
+/**
+ * Removes a child control.  Overrides {@link goog.ui.Component#removeChild} by
+ * updating the highlight index.  Since {@link goog.ui.Component#removeChildAt}
+ * uses {@link #removeChild} internally, we only need to override this method.
+ * @param {string|goog.ui.Component} control The ID of the child to remove, or
+ *     the control itself.
+ * @param {boolean=} opt_unrender Whether to call {@code exitDocument} on the
+ *     removed control, and detach its DOM from the document (defaults to
+ *     false).
+ * @return {goog.ui.Control} The removed control, if any.
+ * @override
+ */
+goog.ui.Container.prototype.removeChild = function(control, opt_unrender) {
+  control = goog.isString(control) ? this.getChild(control) : control;
+
+  if (control) {
+    var index = this.indexOfChild(control);
+    if (index != -1) {
+      if (index == this.highlightedIndex_) {
+        control.setHighlighted(false);
+        this.highlightedIndex_ = -1;
+      } else if (index < this.highlightedIndex_) {
+        this.highlightedIndex_--;
+      }
+    }
+
+    // Remove the mapping from the child element ID map.
+    var childElem = control.getElement();
+    if (childElem && childElem.id && this.childElementIdMap_) {
+      goog.object.remove(this.childElementIdMap_, childElem.id);
+    }
+  }
+
+  control = /** @type {goog.ui.Control} */ (
+      goog.ui.Container.superClass_.removeChild.call(this, control,
+          opt_unrender));
+
+  // Re-enable mouse event handling (in case the control is reused elsewhere).
+  control.setHandleMouseEvents(true);
+
+  return control;
+};
+
+
+// Container state management.
+
+
+/**
+ * Returns the container's orientation.
+ * @return {?goog.ui.Container.Orientation} Container orientation.
+ */
+goog.ui.Container.prototype.getOrientation = function() {
+  return this.orientation_;
+};
+
+
+/**
+ * Sets the container's orientation.
+ * @param {goog.ui.Container.Orientation} orientation Container orientation.
+ */
+// TODO(attila): Do we need to support containers with dynamic orientation?
+goog.ui.Container.prototype.setOrientation = function(orientation) {
+  if (this.getElement()) {
+    // Too late.
+    throw Error(goog.ui.Component.Error.ALREADY_RENDERED);
+  }
+
+  this.orientation_ = orientation;
+};
+
+
+/**
+ * Returns true if the container's visibility is set to visible, false if
+ * it is set to hidden.  A container that is set to hidden is guaranteed
+ * to be hidden from the user, but the reverse isn't necessarily true.
+ * A container may be set to visible but can otherwise be obscured by another
+ * element, rendered off-screen, or hidden using direct CSS manipulation.
+ * @return {boolean} Whether the container is set to be visible.
+ */
+goog.ui.Container.prototype.isVisible = function() {
+  return this.visible_;
+};
+
+
+/**
+ * Shows or hides the container.  Does nothing if the container already has
+ * the requested visibility.  Otherwise, dispatches a SHOW or HIDE event as
+ * appropriate, giving listeners a chance to prevent the visibility change.
+ * @param {boolean} visible Whether to show or hide the container.
+ * @param {boolean=} opt_force If true, doesn't check whether the container
+ *     already has the requested visibility, and doesn't dispatch any events.
+ * @return {boolean} Whether the visibility was changed.
+ */
+goog.ui.Container.prototype.setVisible = function(visible, opt_force) {
+  if (opt_force || (this.visible_ != visible && this.dispatchEvent(visible ?
+      goog.ui.Component.EventType.SHOW : goog.ui.Component.EventType.HIDE))) {
+    this.visible_ = visible;
+
+    var elem = this.getElement();
+    if (elem) {
+      goog.style.setElementShown(elem, visible);
+      if (this.isFocusable()) {
+        // Enable keyboard access only for enabled & visible containers.
+        this.renderer_.enableTabIndex(this.getKeyEventTarget(),
+            this.enabled_ && this.visible_);
+      }
+      if (!opt_force) {
+        this.dispatchEvent(this.visible_ ?
+            goog.ui.Container.EventType.AFTER_SHOW :
+            goog.ui.Container.EventType.AFTER_HIDE);
+      }
+    }
+
+    return true;
+  }
+
+  return false;
+};
+
+
+/**
+ * Returns true if the container is enabled, false otherwise.
+ * @return {boolean} Whether the container is enabled.
+ */
+goog.ui.Container.prototype.isEnabled = function() {
+  return this.enabled_;
+};
+
+
+/**
+ * Enables/disables the container based on the {@code enable} argument.
+ * Dispatches an {@code ENABLED} or {@code DISABLED} event prior to changing
+ * the container's state, which may be caught and canceled to prevent the
+ * container from changing state.  Also enables/disables child controls.
+ * @param {boolean} enable Whether to enable or disable the container.
+ */
+goog.ui.Container.prototype.setEnabled = function(enable) {
+  if (this.enabled_ != enable && this.dispatchEvent(enable ?
+      goog.ui.Component.EventType.ENABLE :
+      goog.ui.Component.EventType.DISABLE)) {
+    if (enable) {
+      // Flag the container as enabled first, then update children.  This is
+      // because controls can't be enabled if their parent is disabled.
+      this.enabled_ = true;
+      this.forEachChild(function(child) {
+        // Enable child control unless it is flagged.
+        if (child.wasDisabled) {
+          delete child.wasDisabled;
+        } else {
+          child.setEnabled(true);
+        }
+      });
+    } else {
+      // Disable children first, then flag the container as disabled.  This is
+      // because controls can't be disabled if their parent is already disabled.
+      this.forEachChild(function(child) {
+        // Disable child control, or flag it if it's already disabled.
+        if (child.isEnabled()) {
+          child.setEnabled(false);
+        } else {
+          child.wasDisabled = true;
+        }
+      });
+      this.enabled_ = false;
+      this.setMouseButtonPressed(false);
+    }
+
+    if (this.isFocusable()) {
+      // Enable keyboard access only for enabled & visible components.
+      this.renderer_.enableTabIndex(this.getKeyEventTarget(),
+          enable && this.visible_);
+    }
+  }
+};
+
+
+/**
+ * Returns true if the container is focusable, false otherwise.  The default
+ * is true.  Focusable containers always have a tab index and allocate a key
+ * handler to handle keyboard events while focused.
+ * @return {boolean} Whether the component is focusable.
+ */
+goog.ui.Container.prototype.isFocusable = function() {
+  return this.focusable_;
+};
+
+
+/**
+ * Sets whether the container is focusable.  The default is true.  Focusable
+ * containers always have a tab index and allocate a key handler to handle
+ * keyboard events while focused.
+ * @param {boolean} focusable Whether the component is to be focusable.
+ */
+goog.ui.Container.prototype.setFocusable = function(focusable) {
+  if (focusable != this.focusable_ && this.isInDocument()) {
+    this.enableFocusHandling_(focusable);
+  }
+  this.focusable_ = focusable;
+  if (this.enabled_ && this.visible_) {
+    this.renderer_.enableTabIndex(this.getKeyEventTarget(), focusable);
+  }
+};
+
+
+/**
+ * Returns true if the container allows children to be focusable, false
+ * otherwise.  Only effective if the container is not focusable.
+ * @return {boolean} Whether children should be focusable.
+ */
+goog.ui.Container.prototype.isFocusableChildrenAllowed = function() {
+  return this.allowFocusableChildren_;
+};
+
+
+/**
+ * Sets whether the container allows children to be focusable, false
+ * otherwise.  Only effective if the container is not focusable.
+ * @param {boolean} focusable Whether the children should be focusable.
+ */
+goog.ui.Container.prototype.setFocusableChildrenAllowed = function(focusable) {
+  this.allowFocusableChildren_ = focusable;
+};
+
+
+/**
+ * @return {boolean} Whether highlighting a child component should also open it.
+ */
+goog.ui.Container.prototype.isOpenFollowsHighlight = function() {
+  return this.openFollowsHighlight_;
+};
+
+
+/**
+ * Sets whether highlighting a child component should also open it.
+ * @param {boolean} follow Whether highlighting a child component also opens it.
+ */
+goog.ui.Container.prototype.setOpenFollowsHighlight = function(follow) {
+  this.openFollowsHighlight_ = follow;
+};
+
+
+// Highlight management.
+
+
+/**
+ * Returns the index of the currently highlighted item (-1 if none).
+ * @return {number} Index of the currently highlighted item.
+ */
+goog.ui.Container.prototype.getHighlightedIndex = function() {
+  return this.highlightedIndex_;
+};
+
+
+/**
+ * Highlights the item at the given 0-based index (if any).  If another item
+ * was previously highlighted, it is un-highlighted.
+ * @param {number} index Index of item to highlight (-1 removes the current
+ *     highlight).
+ */
+goog.ui.Container.prototype.setHighlightedIndex = function(index) {
+  var child = this.getChildAt(index);
+  if (child) {
+    child.setHighlighted(true);
+  } else if (this.highlightedIndex_ > -1) {
+    this.getHighlighted().setHighlighted(false);
+  }
+};
+
+
+/**
+ * Highlights the given item if it exists and is a child of the container;
+ * otherwise un-highlights the currently highlighted item.
+ * @param {goog.ui.Control} item Item to highlight.
+ */
+goog.ui.Container.prototype.setHighlighted = function(item) {
+  this.setHighlightedIndex(this.indexOfChild(item));
+};
+
+
+/**
+ * Returns the currently highlighted item (if any).
+ * @return {goog.ui.Control?} Highlighted item (null if none).
+ */
+goog.ui.Container.prototype.getHighlighted = function() {
+  return this.getChildAt(this.highlightedIndex_);
+};
+
+
+/**
+ * Highlights the first highlightable item in the container
+ */
+goog.ui.Container.prototype.highlightFirst = function() {
+  this.highlightHelper(function(index, max) {
+    return (index + 1) % max;
+  }, this.getChildCount() - 1);
+};
+
+
+/**
+ * Highlights the last highlightable item in the container.
+ */
+goog.ui.Container.prototype.highlightLast = function() {
+  this.highlightHelper(function(index, max) {
+    index--;
+    return index < 0 ? max - 1 : index;
+  }, 0);
+};
+
+
+/**
+ * Highlights the next highlightable item (or the first if nothing is currently
+ * highlighted).
+ */
+goog.ui.Container.prototype.highlightNext = function() {
+  this.highlightHelper(function(index, max) {
+    return (index + 1) % max;
+  }, this.highlightedIndex_);
+};
+
+
+/**
+ * Highlights the previous highlightable item (or the last if nothing is
+ * currently highlighted).
+ */
+goog.ui.Container.prototype.highlightPrevious = function() {
+  this.highlightHelper(function(index, max) {
+    index--;
+    return index < 0 ? max - 1 : index;
+  }, this.highlightedIndex_);
+};
+
+
+/**
+ * Helper function that manages the details of moving the highlight among
+ * child controls in response to keyboard events.
+ * @param {function(number, number) : number} fn Function that accepts the
+ *     current and maximum indices, and returns the next index to check.
+ * @param {number} startIndex Start index.
+ * @return {boolean} Whether the highlight has changed.
+ * @protected
+ */
+goog.ui.Container.prototype.highlightHelper = function(fn, startIndex) {
+  // If the start index is -1 (meaning there's nothing currently highlighted),
+  // try starting from the currently open item, if any.
+  var curIndex = startIndex < 0 ?
+      this.indexOfChild(this.openItem_) : startIndex;
+  var numItems = this.getChildCount();
+
+  curIndex = fn.call(this, curIndex, numItems);
+  var visited = 0;
+  while (visited <= numItems) {
+    var control = this.getChildAt(curIndex);
+    if (control && this.canHighlightItem(control)) {
+      this.setHighlightedIndexFromKeyEvent(curIndex);
+      return true;
+    }
+    visited++;
+    curIndex = fn.call(this, curIndex, numItems);
+  }
+  return false;
+};
+
+
+/**
+ * Returns whether the given item can be highlighted.
+ * @param {goog.ui.Control} item The item to check.
+ * @return {boolean} Whether the item can be highlighted.
+ * @protected
+ */
+goog.ui.Container.prototype.canHighlightItem = function(item) {
+  return item.isVisible() && item.isEnabled() &&
+      item.isSupportedState(goog.ui.Component.State.HOVER);
+};
+
+
+/**
+ * Helper method that sets the highlighted index to the given index in response
+ * to a keyboard event.  The base class implementation simply calls the
+ * {@link #setHighlightedIndex} method, but subclasses can override this
+ * behavior as needed.
+ * @param {number} index Index of item to highlight.
+ * @protected
+ */
+goog.ui.Container.prototype.setHighlightedIndexFromKeyEvent = function(index) {
+  this.setHighlightedIndex(index);
+};
+
+
+/**
+ * Returns the currently open (expanded) control in the container (null if
+ * none).
+ * @return {goog.ui.Control?} The currently open control.
+ */
+goog.ui.Container.prototype.getOpenItem = function() {
+  return this.openItem_;
+};
+
+
+/**
+ * Returns true if the mouse button is pressed, false otherwise.
+ * @return {boolean} Whether the mouse button is pressed.
+ */
+goog.ui.Container.prototype.isMouseButtonPressed = function() {
+  return this.mouseButtonPressed_;
+};
+
+
+/**
+ * Sets or clears the "mouse button pressed" flag.
+ * @param {boolean} pressed Whether the mouse button is presed.
+ */
+goog.ui.Container.prototype.setMouseButtonPressed = function(pressed) {
+  this.mouseButtonPressed_ = pressed;
+};