chrome/browser/resources/uber/uber.js - platform/external/chromium_org - Git at Google

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 cr.define('uber', function() {
   /**
    * Options for how web history should be handled.
    */
   var HISTORY_STATE_OPTION = {
     PUSH: 1,    // Push a new history state.
     REPLACE: 2, // Replace the current history state.
     NONE: 3,    // Ignore this history state change.
   };

   /**
    * We cache a reference to the #navigation frame here so we don't need to grab
    * it from the DOM on each scroll.
    * @type {Node}
    * @private
    */
   var navFrame;

   /**
    * A queue of method invocations on one of the iframes; if the iframe has not
    * loaded by the time there is a method to invoke, delay the invocation until
    * it is ready.
    * @type {Object}
    * @private
    */
   var queuedInvokes = {};

   /**
    * Handles page initialization.
    */
   function onLoad(e) {
     navFrame = $('navigation');
     navFrame.dataset.width = navFrame.offsetWidth;

     // Select a page based on the page-URL.
     var params = resolvePageInfo();
     showPage(params.id, HISTORY_STATE_OPTION.NONE, params.path);

     window.addEventListener('message', handleWindowMessage);
     window.setTimeout(function() {
       document.documentElement.classList.remove('loading');
     }, 0);

     // HACK(dbeam): This makes the assumption that any second part to a path
     // will result in needing background navigation. We shortcut it to avoid
     // flicker on load.
     // HACK(csilv): Search URLs aren't overlays, special case them.
     if (params.id == 'settings' && params.path &&
         params.path.indexOf('search') != 0) {
       backgroundNavigation();
     }

     ensureNonSelectedFrameContainersAreHidden();
   }

   /**
    * Find page information from window.location. If the location doesn't
    * point to one of our pages, return default parameters.
    * @return {Object} An object containing the following parameters:
    *     id - The 'id' of the page.
    *     path - A path into the page, including search and hash. Optional.
    */
   function resolvePageInfo() {
     var params = {};
     var path = window.location.pathname;
     if (path.length > 1) {
       // Split the path into id and the remaining path.
       path = path.slice(1);
       var index = path.indexOf('/');
       if (index != -1) {
         params.id = path.slice(0, index);
         params.path = path.slice(index + 1);
       } else {
         params.id = path;
       }

       var container = $(params.id);
       if (container) {
         // The id is valid. Add the hash and search parts of the URL to path.
         params.path = (params.path || '') + window.location.search +
             window.location.hash;
       } else {
         // The target sub-page does not exist, discard the params we generated.
         params.id = undefined;
         params.path = undefined;
       }
     }
     // If we don't have a valid page, get a default.
     if (!params.id)
       params.id = getDefaultIframe().id;

     return params;
   }

   /**
    * Handler for window.onpopstate.
    * @param {Event} e The history event.
    */
   function onPopHistoryState(e) {
     // Use the URL to determine which page to route to.
     var params = resolvePageInfo();

     // If the page isn't the current page, load it fresh. Even if the page is
     // already loaded, it may have state not reflected in the URL, such as the
     // history page's "Remove selected items" overlay. http://crbug.com/377386
     if (getRequiredElement(params.id) !== getSelectedIframe())
       showPage(params.id, HISTORY_STATE_OPTION.NONE, params.path);

     // Either way, send the state down to it.
     //
     // Note: This assumes that the state and path parameters for every page
     // under this origin are compatible. All of the downstream pages which
     // navigate use pushState and replaceState.
     invokeMethodOnPage(params.id, 'popState',
                        {state: e.state, path: '/' + params.path});
   }

   /**
    * @return {Object} The default iframe container.
    */
   function getDefaultIframe() {
     return $(loadTimeData.getString('helpHost'));
   }

   /**
    * @return {Object} The currently selected iframe container.
    */
   function getSelectedIframe() {
     return document.querySelector('.iframe-container.selected');
   }

   /**
    * Handles postMessage calls from the iframes of the contained pages.
    *
    * The pages request functionality from this object by passing an object of
    * the following form:
    *
    *  { method : "methodToInvoke",
    *    params : {...}
    *  }
    *
    * |method| is required, while |params| is optional. Extra parameters required
    * by a method must be specified by that method's documentation.
    *
    * @param {Event} e The posted object.
    */
   function handleWindowMessage(e) {
     e = /** @type{!MessageEvent.<!{method: string, params: *}>} */(e);
     if (e.data.method === 'beginInterceptingEvents') {
       backgroundNavigation();
     } else if (e.data.method === 'stopInterceptingEvents') {
       foregroundNavigation();
     } else if (e.data.method === 'ready') {
       pageReady(e.origin);
     } else if (e.data.method === 'updateHistory') {
       updateHistory(e.origin, e.data.params.state, e.data.params.path,
                     e.data.params.replace);
     } else if (e.data.method === 'setTitle') {
       setTitle(e.origin, e.data.params.title);
     } else if (e.data.method === 'showPage') {
       showPage(e.data.params.pageId,
                HISTORY_STATE_OPTION.PUSH,
                e.data.params.path);
     } else if (e.data.method === 'navigationControlsLoaded') {
       onNavigationControlsLoaded();
     } else if (e.data.method === 'adjustToScroll') {
       adjustToScroll(/** @type {number} */(e.data.params));
     } else if (e.data.method === 'mouseWheel') {
       forwardMouseWheel(/** @type {Object} */(e.data.params));
     } else {
       console.error('Received unexpected message', e.data);
     }
   }

   /**
    * Sends the navigation iframe to the background.
    */
   function backgroundNavigation() {
     navFrame.classList.add('background');
     navFrame.firstChild.tabIndex = -1;
     navFrame.firstChild.setAttribute('aria-hidden', true);
   }

   /**
    * Retrieves the navigation iframe from the background.
    */
   function foregroundNavigation() {
     navFrame.classList.remove('background');
     navFrame.firstChild.tabIndex = 0;
     navFrame.firstChild.removeAttribute('aria-hidden');
   }

   /**
    * Enables or disables animated transitions when changing content while
    * horizontally scrolled.
    * @param {boolean} enabled True if enabled, else false to disable.
    */
   function setContentChanging(enabled) {
     navFrame.classList[enabled ? 'add' : 'remove']('changing-content');

     if (isRTL()) {
       uber.invokeMethodOnWindow(navFrame.firstChild.contentWindow,
                                 'setContentChanging', enabled);
     }
   }

   /**
    * Get an iframe based on the origin of a received post message.
    * @param {string} origin The origin of a post message.
    * @return {!Element} The frame associated to |origin| or null.
    */
   function getIframeFromOrigin(origin) {
     assert(origin.substr(-1) != '/', 'invalid origin given');
     var query = '.iframe-container > iframe[src^="' + origin + '/"]';
     var element = document.querySelector(query);
     assert(element);
     return /** @type {!Element} */(element);
   }

   /**
    * Changes the path past the page title (i.e. chrome://chrome/settings/(.*)).
    * @param {Object} state The page's state object for the navigation.
    * @param {string} path The new /path/ to be set after the page name.
    * @param {number} historyOption The type of history modification to make.
    */
   function changePathTo(state, path, historyOption) {
     assert(!path || path.substr(-1) != '/', 'invalid path given');

     var histFunc;
     if (historyOption == HISTORY_STATE_OPTION.PUSH)
       histFunc = window.history.pushState;
     else if (historyOption == HISTORY_STATE_OPTION.REPLACE)
       histFunc = window.history.replaceState;

     assert(histFunc, 'invalid historyOption given ' + historyOption);

     var pageId = getSelectedIframe().id;
     var args = [state, '', '/' + pageId + '/' + (path || '')];
     histFunc.apply(window.history, args);
   }

   /**
    * Adds or replaces the current history entry based on a navigation from the
    * source iframe.
    * @param {string} origin The origin of the source iframe.
    * @param {Object} state The source iframe's state object.
    * @param {string} path The new "path" (e.g. "/createProfile").
    * @param {boolean} replace Whether to replace the current history entry.
    */
   function updateHistory(origin, state, path, replace) {
     assert(!path || path[0] != '/', 'invalid path sent from ' + origin);
     var historyOption =
         replace ? HISTORY_STATE_OPTION.REPLACE : HISTORY_STATE_OPTION.PUSH;
     // Only update the currently displayed path if this is the visible frame.
     var container = getIframeFromOrigin(origin).parentNode;
     if (container == getSelectedIframe())
       changePathTo(state, path, historyOption);
   }

   /**
    * Sets the title of the page.
    * @param {string} origin The origin of the source iframe.
    * @param {string} title The title of the page.
    */
   function setTitle(origin, title) {
     // Cache the title for the client iframe, i.e., the iframe setting the
     // title. querySelector returns the actual iframe element, so use parentNode
     // to get back to the container.
     var container = getIframeFromOrigin(origin).parentNode;
     container.dataset.title = title;

     // Only update the currently displayed title if this is the visible frame.
     if (container == getSelectedIframe())
       document.title = title;
   }

   /**
    * Invokes a method on a subpage. If the subpage has not signaled readiness,
    * queue the message for when it does.
    * @param {string} pageId Should match an id of one of the iframe containers.
    * @param {string} method The name of the method to invoke.
    * @param {Object=} opt_params Optional property page of parameters to pass to
    *     the invoked method.
    */
   function invokeMethodOnPage(pageId, method, opt_params) {
     var frame = $(pageId).querySelector('iframe');
     if (!frame || !frame.dataset.ready) {
       queuedInvokes[pageId] = (queuedInvokes[pageId] || []);
       queuedInvokes[pageId].push([method, opt_params]);
     } else {
       uber.invokeMethodOnWindow(frame.contentWindow, method, opt_params);
     }
   }

   /**
    * Called in response to a page declaring readiness. Calls any deferred method
    * invocations from invokeMethodOnPage.
    * @param {string} origin The origin of the source iframe.
    */
   function pageReady(origin) {
     var frame = getIframeFromOrigin(origin);
     var container = frame.parentNode;
     frame.dataset.ready = true;
     var queue = queuedInvokes[container.id] || [];
     queuedInvokes[container.id] = undefined;
     for (var i = 0; i < queue.length; i++) {
       uber.invokeMethodOnWindow(frame.contentWindow, queue[i][0], queue[i][1]);
     }
   }

   /**
    * Selects and navigates a subpage. This is called from uber-frame.
    * @param {string} pageId Should match an id of one of the iframe containers.
    * @param {number} historyOption Indicates whether we should push or replace
    *     browser history.
    * @param {string} path A sub-page path.
    */
   function showPage(pageId, historyOption, path) {
     var container = $(pageId);

     // Lazy load of iframe contents.
     var sourceUrl = container.dataset.url + (path || '');
     var frame = container.querySelector('iframe');
     if (!frame) {
       frame = container.ownerDocument.createElement('iframe');
       frame.name = pageId;
       container.appendChild(frame);
       frame.src = sourceUrl;
     } else {
       // There's no particularly good way to know what the current URL of the
       // content frame is as we don't have access to its contentWindow's
       // location, so just replace every time until necessary to do otherwise.
       frame.contentWindow.location.replace(sourceUrl);
       frame.dataset.ready = false;
     }

     // If the last selected container is already showing, ignore the rest.
     var lastSelected = document.querySelector('.iframe-container.selected');
     if (lastSelected === container)
       return;

     if (lastSelected) {
       lastSelected.classList.remove('selected');
       // Setting aria-hidden hides the container from assistive technology
       // immediately. The 'hidden' attribute is set after the transition
       // finishes - that ensures it's not possible to accidentally focus
       // an element in an unselected container.
       lastSelected.setAttribute('aria-hidden', 'true');
     }

     // Containers that aren't selected have to be hidden so that their
     // content isn't focusable.
     container.hidden = false;
     container.setAttribute('aria-hidden', 'false');

     // Trigger a layout after making it visible and before setting
     // the class to 'selected', so that it animates in.
     /** @suppress {uselessCode} */
     container.offsetTop;
     container.classList.add('selected');

     setContentChanging(true);
     adjustToScroll(0);

     var selectedFrame = getSelectedIframe().querySelector('iframe');
     uber.invokeMethodOnWindow(selectedFrame.contentWindow, 'frameSelected');
     selectedFrame.contentWindow.focus();

     if (historyOption != HISTORY_STATE_OPTION.NONE)
       changePathTo({}, path, historyOption);

     if (container.dataset.title)
       document.title = container.dataset.title;
     assert('favicon' in container.dataset);

     var dataset = /** @type {{favicon: string}} */(container.dataset);
     $('favicon').href = 'chrome://theme/' + dataset.favicon;
     $('favicon2x').href = 'chrome://theme/' + dataset.favicon + '@2x';

     updateNavigationControls();
   }

   function onNavigationControlsLoaded() {
     updateNavigationControls();
   }

   /**
    * Sends a message to uber-frame to update the appearance of the nav controls.
    * It should be called whenever the selected iframe changes.
    */
   function updateNavigationControls() {
     var iframe = getSelectedIframe();
     uber.invokeMethodOnWindow(navFrame.firstChild.contentWindow,
                               'changeSelection', {pageId: iframe.id});
   }

   /**
    * Forwarded scroll offset from a content frame's scroll handler.
    * @param {number} scrollOffset The scroll offset from the content frame.
    */
   function adjustToScroll(scrollOffset) {
     // NOTE: The scroll is reset to 0 and easing turned on every time a user
     // switches frames. If we receive a non-zero value it has to have come from
     // a real user scroll, so we disable easing when this happens.
     if (scrollOffset != 0)
       setContentChanging(false);

     if (isRTL()) {
       uber.invokeMethodOnWindow(navFrame.firstChild.contentWindow,
                                 'adjustToScroll',
                                 scrollOffset);
       var navWidth = Math.max(0, +navFrame.dataset.width + scrollOffset);
       navFrame.style.width = navWidth + 'px';
     } else {
       navFrame.style.webkitTransform = 'translateX(' + -scrollOffset + 'px)';
     }
   }

   /**
    * Forward scroll wheel events to subpages.
    * @param {Object} params Relevant parameters of wheel event.
    */
   function forwardMouseWheel(params) {
     var iframe = getSelectedIframe().querySelector('iframe');
     uber.invokeMethodOnWindow(iframe.contentWindow, 'mouseWheel', params);
   }

   /**
    * Make sure that iframe containers that are not selected are
    * hidden, so that elements in those frames aren't part of the
    * focus order. Containers that are unselected later get hidden
    * when the transition ends. We also set the aria-hidden attribute
    * because that hides the container from assistive technology
    * immediately, rather than only after the transition ends.
    */
   function ensureNonSelectedFrameContainersAreHidden() {
     var containers = document.querySelectorAll('.iframe-container');
     for (var i = 0; i < containers.length; i++) {
       var container = containers[i];
       if (!container.classList.contains('selected')) {
         container.hidden = true;
         container.setAttribute('aria-hidden', 'true');
       }
       container.addEventListener('webkitTransitionEnd', function(event) {
         if (!event.target.classList.contains('selected'))
           event.target.hidden = true;
       });
     }
   }

   return {
     onLoad: onLoad,
     onPopHistoryState: onPopHistoryState
   };
 });

 window.addEventListener('popstate', uber.onPopHistoryState);
 document.addEventListener('DOMContentLoaded', uber.onLoad);
	// Copyright (c) 2012 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	cr.define('uber', function() {
	/**
	* Options for how web history should be handled.
	*/
	var HISTORY_STATE_OPTION = {
	PUSH: 1, // Push a new history state.
	REPLACE: 2, // Replace the current history state.
	NONE: 3, // Ignore this history state change.
	};

	/**
	* We cache a reference to the #navigation frame here so we don't need to grab
	* it from the DOM on each scroll.
	* @type {Node}
	* @private
	*/
	var navFrame;

	/**
	* A queue of method invocations on one of the iframes; if the iframe has not
	* loaded by the time there is a method to invoke, delay the invocation until
	* it is ready.
	* @type {Object}
	* @private
	*/
	var queuedInvokes = {};

	/**
	* Handles page initialization.
	*/
	function onLoad(e) {
	navFrame = $('navigation');
	navFrame.dataset.width = navFrame.offsetWidth;

	// Select a page based on the page-URL.
	var params = resolvePageInfo();
	showPage(params.id, HISTORY_STATE_OPTION.NONE, params.path);

	window.addEventListener('message', handleWindowMessage);
	window.setTimeout(function() {
	document.documentElement.classList.remove('loading');
	}, 0);

	// HACK(dbeam): This makes the assumption that any second part to a path
	// will result in needing background navigation. We shortcut it to avoid
	// flicker on load.
	// HACK(csilv): Search URLs aren't overlays, special case them.
	if (params.id == 'settings' && params.path &&
	params.path.indexOf('search') != 0) {
	backgroundNavigation();
	}

	ensureNonSelectedFrameContainersAreHidden();
	}

	/**
	* Find page information from window.location. If the location doesn't
	* point to one of our pages, return default parameters.
	* @return {Object} An object containing the following parameters:
	* id - The 'id' of the page.
	* path - A path into the page, including search and hash. Optional.
	*/
	function resolvePageInfo() {
	var params = {};
	var path = window.location.pathname;
	if (path.length > 1) {
	// Split the path into id and the remaining path.
	path = path.slice(1);
	var index = path.indexOf('/');
	if (index != -1) {
	params.id = path.slice(0, index);
	params.path = path.slice(index + 1);
	} else {
	params.id = path;
	}

	var container = $(params.id);
	if (container) {
	// The id is valid. Add the hash and search parts of the URL to path.
	params.path = (params.path \|\| '') + window.location.search +
	window.location.hash;
	} else {
	// The target sub-page does not exist, discard the params we generated.
	params.id = undefined;
	params.path = undefined;
	}
	}
	// If we don't have a valid page, get a default.
	if (!params.id)
	params.id = getDefaultIframe().id;

	return params;
	}

	/**
	* Handler for window.onpopstate.
	* @param {Event} e The history event.
	*/
	function onPopHistoryState(e) {
	// Use the URL to determine which page to route to.
	var params = resolvePageInfo();

	// If the page isn't the current page, load it fresh. Even if the page is
	// already loaded, it may have state not reflected in the URL, such as the
	// history page's "Remove selected items" overlay. http://crbug.com/377386
	if (getRequiredElement(params.id) !== getSelectedIframe())
	showPage(params.id, HISTORY_STATE_OPTION.NONE, params.path);

	// Either way, send the state down to it.
	//
	// Note: This assumes that the state and path parameters for every page
	// under this origin are compatible. All of the downstream pages which
	// navigate use pushState and replaceState.
	invokeMethodOnPage(params.id, 'popState',
	{state: e.state, path: '/' + params.path});
	}

	/**
	* @return {Object} The default iframe container.
	*/
	function getDefaultIframe() {
	return $(loadTimeData.getString('helpHost'));
	}

	/**
	* @return {Object} The currently selected iframe container.
	*/
	function getSelectedIframe() {
	return document.querySelector('.iframe-container.selected');
	}

	/**
	* Handles postMessage calls from the iframes of the contained pages.
	*
	* The pages request functionality from this object by passing an object of
	* the following form:
	*
	* { method : "methodToInvoke",
	* params : {...}
	* }
	*
	* \|method\| is required, while \|params\| is optional. Extra parameters required
	* by a method must be specified by that method's documentation.
	*
	* @param {Event} e The posted object.
	*/
	function handleWindowMessage(e) {
	e = /** @type{!MessageEvent.<!{method: string, params: }>} /(e);
	if (e.data.method === 'beginInterceptingEvents') {
	backgroundNavigation();
	} else if (e.data.method === 'stopInterceptingEvents') {
	foregroundNavigation();
	} else if (e.data.method === 'ready') {
	pageReady(e.origin);
	} else if (e.data.method === 'updateHistory') {
	updateHistory(e.origin, e.data.params.state, e.data.params.path,
	e.data.params.replace);
	} else if (e.data.method === 'setTitle') {
	setTitle(e.origin, e.data.params.title);
	} else if (e.data.method === 'showPage') {
	showPage(e.data.params.pageId,
	HISTORY_STATE_OPTION.PUSH,
	e.data.params.path);
	} else if (e.data.method === 'navigationControlsLoaded') {
	onNavigationControlsLoaded();
	} else if (e.data.method === 'adjustToScroll') {
	adjustToScroll(/** @type {number} */(e.data.params));
	} else if (e.data.method === 'mouseWheel') {
	forwardMouseWheel(/** @type {Object} */(e.data.params));
	} else {
	console.error('Received unexpected message', e.data);
	}
	}

	/**
	* Sends the navigation iframe to the background.
	*/
	function backgroundNavigation() {
	navFrame.classList.add('background');
	navFrame.firstChild.tabIndex = -1;
	navFrame.firstChild.setAttribute('aria-hidden', true);
	}

	/**
	* Retrieves the navigation iframe from the background.
	*/
	function foregroundNavigation() {
	navFrame.classList.remove('background');
	navFrame.firstChild.tabIndex = 0;
	navFrame.firstChild.removeAttribute('aria-hidden');
	}

	/**
	* Enables or disables animated transitions when changing content while
	* horizontally scrolled.
	* @param {boolean} enabled True if enabled, else false to disable.
	*/
	function setContentChanging(enabled) {
	navFrame.classList[enabled ? 'add' : 'remove']('changing-content');

	if (isRTL()) {
	uber.invokeMethodOnWindow(navFrame.firstChild.contentWindow,
	'setContentChanging', enabled);
	}
	}

	/**
	* Get an iframe based on the origin of a received post message.
	* @param {string} origin The origin of a post message.
	* @return {!Element} The frame associated to \|origin\| or null.
	*/
	function getIframeFromOrigin(origin) {
	assert(origin.substr(-1) != '/', 'invalid origin given');
	var query = '.iframe-container > iframe[src^="' + origin + '/"]';
	var element = document.querySelector(query);
	assert(element);
	return /** @type {!Element} */(element);
	}

	/**
	* Changes the path past the page title (i.e. chrome://chrome/settings/(.*)).
	* @param {Object} state The page's state object for the navigation.
	* @param {string} path The new /path/ to be set after the page name.
	* @param {number} historyOption The type of history modification to make.
	*/
	function changePathTo(state, path, historyOption) {
	assert(!path \|\| path.substr(-1) != '/', 'invalid path given');

	var histFunc;
	if (historyOption == HISTORY_STATE_OPTION.PUSH)
	histFunc = window.history.pushState;
	else if (historyOption == HISTORY_STATE_OPTION.REPLACE)
	histFunc = window.history.replaceState;

	assert(histFunc, 'invalid historyOption given ' + historyOption);

	var pageId = getSelectedIframe().id;
	var args = [state, '', '/' + pageId + '/' + (path \|\| '')];
	histFunc.apply(window.history, args);
	}

	/**
	* Adds or replaces the current history entry based on a navigation from the
	* source iframe.
	* @param {string} origin The origin of the source iframe.
	* @param {Object} state The source iframe's state object.
	* @param {string} path The new "path" (e.g. "/createProfile").
	* @param {boolean} replace Whether to replace the current history entry.
	*/
	function updateHistory(origin, state, path, replace) {
	assert(!path \|\| path[0] != '/', 'invalid path sent from ' + origin);
	var historyOption =
	replace ? HISTORY_STATE_OPTION.REPLACE : HISTORY_STATE_OPTION.PUSH;
	// Only update the currently displayed path if this is the visible frame.
	var container = getIframeFromOrigin(origin).parentNode;
	if (container == getSelectedIframe())
	changePathTo(state, path, historyOption);
	}

	/**
	* Sets the title of the page.
	* @param {string} origin The origin of the source iframe.
	* @param {string} title The title of the page.
	*/
	function setTitle(origin, title) {
	// Cache the title for the client iframe, i.e., the iframe setting the
	// title. querySelector returns the actual iframe element, so use parentNode
	// to get back to the container.
	var container = getIframeFromOrigin(origin).parentNode;
	container.dataset.title = title;

	// Only update the currently displayed title if this is the visible frame.
	if (container == getSelectedIframe())
	document.title = title;
	}

	/**
	* Invokes a method on a subpage. If the subpage has not signaled readiness,
	* queue the message for when it does.
	* @param {string} pageId Should match an id of one of the iframe containers.
	* @param {string} method The name of the method to invoke.
	* @param {Object=} opt_params Optional property page of parameters to pass to
	* the invoked method.
	*/
	function invokeMethodOnPage(pageId, method, opt_params) {
	var frame = $(pageId).querySelector('iframe');
	if (!frame \|\| !frame.dataset.ready) {
	queuedInvokes[pageId] = (queuedInvokes[pageId] \|\| []);
	queuedInvokes[pageId].push([method, opt_params]);
	} else {
	uber.invokeMethodOnWindow(frame.contentWindow, method, opt_params);
	}
	}

	/**
	* Called in response to a page declaring readiness. Calls any deferred method
	* invocations from invokeMethodOnPage.
	* @param {string} origin The origin of the source iframe.
	*/
	function pageReady(origin) {
	var frame = getIframeFromOrigin(origin);
	var container = frame.parentNode;
	frame.dataset.ready = true;
	var queue = queuedInvokes[container.id] \|\| [];
	queuedInvokes[container.id] = undefined;
	for (var i = 0; i < queue.length; i++) {
	uber.invokeMethodOnWindow(frame.contentWindow, queue[i][0], queue[i][1]);
	}
	}

	/**
	* Selects and navigates a subpage. This is called from uber-frame.
	* @param {string} pageId Should match an id of one of the iframe containers.
	* @param {number} historyOption Indicates whether we should push or replace
	* browser history.
	* @param {string} path A sub-page path.
	*/
	function showPage(pageId, historyOption, path) {
	var container = $(pageId);

	// Lazy load of iframe contents.
	var sourceUrl = container.dataset.url + (path \|\| '');
	var frame = container.querySelector('iframe');
	if (!frame) {
	frame = container.ownerDocument.createElement('iframe');
	frame.name = pageId;
	container.appendChild(frame);
	frame.src = sourceUrl;
	} else {
	// There's no particularly good way to know what the current URL of the
	// content frame is as we don't have access to its contentWindow's
	// location, so just replace every time until necessary to do otherwise.
	frame.contentWindow.location.replace(sourceUrl);
	frame.dataset.ready = false;
	}

	// If the last selected container is already showing, ignore the rest.
	var lastSelected = document.querySelector('.iframe-container.selected');
	if (lastSelected === container)
	return;

	if (lastSelected) {
	lastSelected.classList.remove('selected');
	// Setting aria-hidden hides the container from assistive technology
	// immediately. The 'hidden' attribute is set after the transition
	// finishes - that ensures it's not possible to accidentally focus
	// an element in an unselected container.
	lastSelected.setAttribute('aria-hidden', 'true');
	}

	// Containers that aren't selected have to be hidden so that their
	// content isn't focusable.
	container.hidden = false;
	container.setAttribute('aria-hidden', 'false');

	// Trigger a layout after making it visible and before setting
	// the class to 'selected', so that it animates in.
	/** @suppress {uselessCode} */
	container.offsetTop;
	container.classList.add('selected');

	setContentChanging(true);
	adjustToScroll(0);

	var selectedFrame = getSelectedIframe().querySelector('iframe');
	uber.invokeMethodOnWindow(selectedFrame.contentWindow, 'frameSelected');
	selectedFrame.contentWindow.focus();

	if (historyOption != HISTORY_STATE_OPTION.NONE)
	changePathTo({}, path, historyOption);

	if (container.dataset.title)
	document.title = container.dataset.title;
	assert('favicon' in container.dataset);

	var dataset = /** @type {{favicon: string}} */(container.dataset);
	$('favicon').href = 'chrome://theme/' + dataset.favicon;
	$('favicon2x').href = 'chrome://theme/' + dataset.favicon + '@2x';

	updateNavigationControls();
	}

	function onNavigationControlsLoaded() {
	updateNavigationControls();
	}

	/**
	* Sends a message to uber-frame to update the appearance of the nav controls.
	* It should be called whenever the selected iframe changes.
	*/
	function updateNavigationControls() {
	var iframe = getSelectedIframe();
	uber.invokeMethodOnWindow(navFrame.firstChild.contentWindow,
	'changeSelection', {pageId: iframe.id});
	}

	/**
	* Forwarded scroll offset from a content frame's scroll handler.
	* @param {number} scrollOffset The scroll offset from the content frame.
	*/
	function adjustToScroll(scrollOffset) {
	// NOTE: The scroll is reset to 0 and easing turned on every time a user
	// switches frames. If we receive a non-zero value it has to have come from
	// a real user scroll, so we disable easing when this happens.
	if (scrollOffset != 0)
	setContentChanging(false);

	if (isRTL()) {
	uber.invokeMethodOnWindow(navFrame.firstChild.contentWindow,
	'adjustToScroll',
	scrollOffset);
	var navWidth = Math.max(0, +navFrame.dataset.width + scrollOffset);
	navFrame.style.width = navWidth + 'px';
	} else {
	navFrame.style.webkitTransform = 'translateX(' + -scrollOffset + 'px)';
	}
	}

	/**
	* Forward scroll wheel events to subpages.
	* @param {Object} params Relevant parameters of wheel event.
	*/
	function forwardMouseWheel(params) {
	var iframe = getSelectedIframe().querySelector('iframe');
	uber.invokeMethodOnWindow(iframe.contentWindow, 'mouseWheel', params);
	}

	/**
	* Make sure that iframe containers that are not selected are
	* hidden, so that elements in those frames aren't part of the
	* focus order. Containers that are unselected later get hidden
	* when the transition ends. We also set the aria-hidden attribute
	* because that hides the container from assistive technology
	* immediately, rather than only after the transition ends.
	*/
	function ensureNonSelectedFrameContainersAreHidden() {
	var containers = document.querySelectorAll('.iframe-container');
	for (var i = 0; i < containers.length; i++) {
	var container = containers[i];
	if (!container.classList.contains('selected')) {
	container.hidden = true;
	container.setAttribute('aria-hidden', 'true');
	}
	container.addEventListener('webkitTransitionEnd', function(event) {
	if (!event.target.classList.contains('selected'))
	event.target.hidden = true;
	});
	}
	}

	return {
	onLoad: onLoad,
	onPopHistoryState: onPopHistoryState
	};
	});

	window.addEventListener('popstate', uber.onPopHistoryState);
	document.addEventListener('DOMContentLoaded', uber.onLoad);