=} opt_values Maps place holder name to value.\n * @param {{html: boolean}=} opt_options Options:\n * html: Escape '<' in str to '<'. Used by Closure Templates where the\n * generated code size and performance is critical which is why {@link\n * goog.html.SafeHtmlFormatter} is not used. The value must be literal true\n * or false.\n * @return {string} message with placeholders filled.\n */\ngoog.getMsg = function(str, opt_values, opt_options) {\n if (opt_options && opt_options.html) {\n // Note that '&' is not replaced because the translation can contain HTML\n // entities.\n str = str.replace(/var x = goog.getMsgWithFallback(MSG_A, MSG_B);\n * where MSG_A and MSG_B were initialized with goog.getMsg.\n *\n * @param {string} a The preferred message.\n * @param {string} b The fallback message.\n * @return {string} The best translated message.\n */\ngoog.getMsgWithFallback = function(a, b) {\n return a;\n};\n\n\n/**\n * Exposes an unobfuscated global namespace path for the given object.\n * Note that fields of the exported object *will* be obfuscated, unless they are\n * exported in turn via this function or goog.exportProperty.\n *\n * Also handy for making public items that are defined in anonymous closures.\n *\n * ex. goog.exportSymbol('public.path.Foo', Foo);\n *\n * ex. goog.exportSymbol('public.path.Foo.staticFunction', Foo.staticFunction);\n * public.path.Foo.staticFunction();\n *\n * ex. goog.exportSymbol('public.path.Foo.prototype.myMethod',\n * Foo.prototype.myMethod);\n * new public.path.Foo().myMethod();\n *\n * @param {string} publicPath Unobfuscated name to export.\n * @param {*} object Object the name should point to.\n * @param {Object=} opt_objectToExportTo The object to add the path to; default\n * is goog.global.\n */\ngoog.exportSymbol = function(publicPath, object, opt_objectToExportTo) {\n goog.exportPath_(publicPath, object, opt_objectToExportTo);\n};\n\n\n/**\n * Exports a property unobfuscated into the object's namespace.\n * ex. goog.exportProperty(Foo, 'staticFunction', Foo.staticFunction);\n * ex. goog.exportProperty(Foo.prototype, 'myMethod', Foo.prototype.myMethod);\n * @param {Object} object Object whose static property is being exported.\n * @param {string} publicName Unobfuscated name to export.\n * @param {*} symbol Object the name should point to.\n */\ngoog.exportProperty = function(object, publicName, symbol) {\n object[publicName] = symbol;\n};\n\n\n/**\n * Inherit the prototype methods from one constructor into another.\n *\n * Usage:\n * \n * function ParentClass(a, b) { }\n * ParentClass.prototype.foo = function(a) { };\n *\n * function ChildClass(a, b, c) {\n * ChildClass.base(this, 'constructor', a, b);\n * }\n * goog.inherits(ChildClass, ParentClass);\n *\n * var child = new ChildClass('a', 'b', 'see');\n * child.foo(); // This works.\n * \n *\n * @param {!Function} childCtor Child class.\n * @param {!Function} parentCtor Parent class.\n * @suppress {strictMissingProperties} superClass_ and base is not defined on\n * Function.\n */\ngoog.inherits = function(childCtor, parentCtor) {\n /** @constructor */\n function tempCtor() {}\n tempCtor.prototype = parentCtor.prototype;\n childCtor.superClass_ = parentCtor.prototype;\n childCtor.prototype = new tempCtor();\n /** @override */\n childCtor.prototype.constructor = childCtor;\n\n /**\n * Calls superclass constructor/method.\n *\n * This function is only available if you use goog.inherits to\n * express inheritance relationships between classes.\n *\n * NOTE: This is a replacement for goog.base and for superClass_\n * property defined in childCtor.\n *\n * @param {!Object} me Should always be \"this\".\n * @param {string} methodName The method name to call. Calling\n * superclass constructor can be done with the special string\n * 'constructor'.\n * @param {...*} var_args The arguments to pass to superclass\n * method/constructor.\n * @return {*} The return value of the superclass method/constructor.\n */\n childCtor.base = function(me, methodName, var_args) {\n // Copying using loop to avoid deop due to passing arguments object to\n // function. This is faster in many JS engines as of late 2014.\n var args = new Array(arguments.length - 2);\n for (var i = 2; i < arguments.length; i++) {\n args[i - 2] = arguments[i];\n }\n return parentCtor.prototype[methodName].apply(me, args);\n };\n};\n\n\n/**\n * Allow for aliasing within scope functions. This function exists for\n * uncompiled code - in compiled code the calls will be inlined and the aliases\n * applied. In uncompiled code the function is simply run since the aliases as\n * written are valid JavaScript.\n *\n *\n * @param {function()} fn Function to call. This function can contain aliases\n * to namespaces (e.g. \"var dom = goog.dom\") or classes\n * (e.g. \"var Timer = goog.Timer\").\n * @deprecated Use goog.module instead.\n */\ngoog.scope = function(fn) {\n if (goog.isInModuleLoader_()) {\n throw new Error('goog.scope is not supported within a module.');\n }\n fn.call(goog.global);\n};\n\n\n/*\n * To support uncompiled, strict mode bundles that use eval to divide source\n * like so:\n * eval('someSource;//# sourceUrl sourcefile.js');\n * We need to export the globally defined symbols \"goog\" and \"COMPILED\".\n * Exporting \"goog\" breaks the compiler optimizations, so we required that\n * be defined externally.\n * NOTE: We don't use goog.exportSymbol here because we don't want to trigger\n * extern generation when that compiler option is enabled.\n */\nif (!COMPILED) {\n goog.global['COMPILED'] = COMPILED;\n}\n\n\n//==============================================================================\n// goog.defineClass implementation\n//==============================================================================\n\n\n/**\n * Creates a restricted form of a Closure \"class\":\n * - from the compiler's perspective, the instance returned from the\n * constructor is sealed (no new properties may be added). This enables\n * better checks.\n * - the compiler will rewrite this definition to a form that is optimal\n * for type checking and optimization (initially this will be a more\n * traditional form).\n *\n * @param {Function} superClass The superclass, Object or null.\n * @param {goog.defineClass.ClassDescriptor} def\n * An object literal describing\n * the class. It may have the following properties:\n * \"constructor\": the constructor function\n * \"statics\": an object literal containing methods to add to the constructor\n * as \"static\" methods or a function that will receive the constructor\n * function as its only parameter to which static properties can\n * be added.\n * all other properties are added to the prototype.\n * @return {!Function} The class constructor.\n * @deprecated Use ES6 class syntax instead.\n */\ngoog.defineClass = function(superClass, def) {\n // TODO(johnlenz): consider making the superClass an optional parameter.\n var constructor = def.constructor;\n var statics = def.statics;\n // Wrap the constructor prior to setting up the prototype and static methods.\n if (!constructor || constructor == Object.prototype.constructor) {\n constructor = function() {\n throw new Error(\n 'cannot instantiate an interface (no constructor defined).');\n };\n }\n\n var cls = goog.defineClass.createSealingConstructor_(constructor, superClass);\n if (superClass) {\n goog.inherits(cls, superClass);\n }\n\n // Remove all the properties that should not be copied to the prototype.\n delete def.constructor;\n delete def.statics;\n\n goog.defineClass.applyProperties_(cls.prototype, def);\n if (statics != null) {\n if (statics instanceof Function) {\n statics(cls);\n } else {\n goog.defineClass.applyProperties_(cls, statics);\n }\n }\n\n return cls;\n};\n\n\n/**\n * @typedef {{\n * constructor: (!Function|undefined),\n * statics: (Object|undefined|function(Function):void)\n * }}\n */\ngoog.defineClass.ClassDescriptor;\n\n\n/**\n * @define {boolean} Whether the instances returned by goog.defineClass should\n * be sealed when possible.\n *\n * When sealing is disabled the constructor function will not be wrapped by\n * goog.defineClass, making it incompatible with ES6 class methods.\n */\ngoog.defineClass.SEAL_CLASS_INSTANCES =\n goog.define('goog.defineClass.SEAL_CLASS_INSTANCES', goog.DEBUG);\n\n\n/**\n * If goog.defineClass.SEAL_CLASS_INSTANCES is enabled and Object.seal is\n * defined, this function will wrap the constructor in a function that seals the\n * results of the provided constructor function.\n *\n * @param {!Function} ctr The constructor whose results maybe be sealed.\n * @param {Function} superClass The superclass constructor.\n * @return {!Function} The replacement constructor.\n * @private\n */\ngoog.defineClass.createSealingConstructor_ = function(ctr, superClass) {\n if (!goog.defineClass.SEAL_CLASS_INSTANCES) {\n // Do now wrap the constructor when sealing is disabled. Angular code\n // depends on this for injection to work properly.\n return ctr;\n }\n\n // Compute whether the constructor is sealable at definition time, rather\n // than when the instance is being constructed.\n var superclassSealable = !goog.defineClass.isUnsealable_(superClass);\n\n /**\n * @this {Object}\n * @return {?}\n */\n var wrappedCtr = function() {\n // Don't seal an instance of a subclass when it calls the constructor of\n // its super class as there is most likely still setup to do.\n var instance = ctr.apply(this, arguments) || this;\n instance[goog.UID_PROPERTY_] = instance[goog.UID_PROPERTY_];\n\n if (this.constructor === wrappedCtr && superclassSealable &&\n Object.seal instanceof Function) {\n Object.seal(instance);\n }\n return instance;\n };\n\n return wrappedCtr;\n};\n\n\n/**\n * @param {Function} ctr The constructor to test.\n * @return {boolean} Whether the constructor has been tagged as unsealable\n * using goog.tagUnsealableClass.\n * @private\n */\ngoog.defineClass.isUnsealable_ = function(ctr) {\n return ctr && ctr.prototype &&\n ctr.prototype[goog.UNSEALABLE_CONSTRUCTOR_PROPERTY_];\n};\n\n\n// TODO(johnlenz): share these values with the goog.object\n/**\n * The names of the fields that are defined on Object.prototype.\n * @type {!Array}\n * @private\n * @const\n */\ngoog.defineClass.OBJECT_PROTOTYPE_FIELDS_ = [\n 'constructor', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable',\n 'toLocaleString', 'toString', 'valueOf'\n];\n\n\n// TODO(johnlenz): share this function with the goog.object\n/**\n * @param {!Object} target The object to add properties to.\n * @param {!Object} source The object to copy properties from.\n * @private\n */\ngoog.defineClass.applyProperties_ = function(target, source) {\n // TODO(johnlenz): update this to support ES5 getters/setters\n\n var key;\n for (key in source) {\n if (Object.prototype.hasOwnProperty.call(source, key)) {\n target[key] = source[key];\n }\n }\n\n // For IE the for-in-loop does not contain any properties that are not\n // enumerable on the prototype object (for example isPrototypeOf from\n // Object.prototype) and it will also not include 'replace' on objects that\n // extend String and change 'replace' (not that it is common for anyone to\n // extend anything except Object).\n for (var i = 0; i < goog.defineClass.OBJECT_PROTOTYPE_FIELDS_.length; i++) {\n key = goog.defineClass.OBJECT_PROTOTYPE_FIELDS_[i];\n if (Object.prototype.hasOwnProperty.call(source, key)) {\n target[key] = source[key];\n }\n }\n};\n\n\n/**\n * Sealing classes breaks the older idiom of assigning properties on the\n * prototype rather than in the constructor. As such, goog.defineClass\n * must not seal subclasses of these old-style classes until they are fixed.\n * Until then, this marks a class as \"broken\", instructing defineClass\n * not to seal subclasses.\n * @param {!Function} ctr The legacy constructor to tag as unsealable.\n */\ngoog.tagUnsealableClass = function(ctr) {\n if (!COMPILED && goog.defineClass.SEAL_CLASS_INSTANCES) {\n ctr.prototype[goog.UNSEALABLE_CONSTRUCTOR_PROPERTY_] = true;\n }\n};\n\n\n/**\n * Name for unsealable tag property.\n * @const @private {string}\n */\ngoog.UNSEALABLE_CONSTRUCTOR_PROPERTY_ = 'goog_defineClass_legacy_unsealable';\n\n\n// There's a bug in the compiler where without collapse properties the\n// Closure namespace defines do not guard code correctly. To help reduce code\n// size also check for !COMPILED even though it redundant until this is fixed.\nif (!COMPILED && goog.DEPENDENCIES_ENABLED) {\n\n /**\n * Tries to detect whether is in the context of an HTML document.\n * @return {boolean} True if it looks like HTML document.\n * @private\n */\n goog.inHtmlDocument_ = function() {\n /** @type {!Document} */\n var doc = goog.global.document;\n return doc != null && 'write' in doc; // XULDocument misses write.\n };\n\n\n /**\n * We'd like to check for if the document readyState is 'loading'; however\n * there are bugs on IE 10 and below where the readyState being anything other\n * than 'complete' is not reliable.\n * @return {boolean}\n * @private\n */\n goog.isDocumentLoading_ = function() {\n // attachEvent is available on IE 6 thru 10 only, and thus can be used to\n // detect those browsers.\n /** @type {!HTMLDocument} */\n var doc = goog.global.document;\n return doc.attachEvent ? doc.readyState != 'complete' :\n doc.readyState == 'loading';\n };\n\n\n /**\n * Tries to detect the base path of base.js script that bootstraps Closure.\n * @private\n */\n goog.findBasePath_ = function() {\n if (goog.global.CLOSURE_BASE_PATH != undefined &&\n // Anti DOM-clobbering runtime check (b/37736576).\n typeof goog.global.CLOSURE_BASE_PATH === 'string') {\n goog.basePath = goog.global.CLOSURE_BASE_PATH;\n return;\n } else if (!goog.inHtmlDocument_()) {\n return;\n }\n /** @type {!Document} */\n var doc = goog.global.document;\n // If we have a currentScript available, use it exclusively.\n var currentScript = doc.currentScript;\n if (currentScript) {\n var scripts = [currentScript];\n } else {\n var scripts = doc.getElementsByTagName('SCRIPT');\n }\n // Search backwards since the current script is in almost all cases the one\n // that has base.js.\n for (var i = scripts.length - 1; i >= 0; --i) {\n var script = /** @type {!HTMLScriptElement} */ (scripts[i]);\n var src = script.src;\n var qmark = src.lastIndexOf('?');\n var l = qmark == -1 ? src.length : qmark;\n if (src.substr(l - 7, 7) == 'base.js') {\n goog.basePath = src.substr(0, l - 7);\n return;\n }\n }\n };\n\n goog.findBasePath_();\n\n /** @struct @constructor @final */\n goog.Transpiler = function() {\n /** @private {?Object} */\n this.requiresTranspilation_ = null;\n /** @private {string} */\n this.transpilationTarget_ = goog.TRANSPILE_TO_LANGUAGE;\n };\n /**\n * Returns a newly created map from language mode string to a boolean\n * indicating whether transpilation should be done for that mode as well as\n * the highest level language that this environment supports.\n *\n * Guaranteed invariant:\n * For any two modes, l1 and l2 where l2 is a newer mode than l1,\n * `map[l1] == true` implies that `map[l2] == true`.\n *\n * Note this method is extracted and used elsewhere, so it cannot rely on\n * anything external (it should easily be able to be transformed into a\n * standalone, top level function).\n *\n * @private\n * @return {{\n * target: string,\n * map: !Object\n * }}\n */\n goog.Transpiler.prototype.createRequiresTranspilation_ = function() {\n var transpilationTarget = 'es3';\n var /** !Object */ requiresTranspilation = {'es3': false};\n var transpilationRequiredForAllLaterModes = false;\n\n /**\n * Adds an entry to requiresTranspliation for the given language mode.\n *\n * IMPORTANT: Calls must be made in order from oldest to newest language\n * mode.\n * @param {string} modeName\n * @param {function(): boolean} isSupported Returns true if the JS engine\n * supports the given mode.\n */\n function addNewerLanguageTranspilationCheck(modeName, isSupported) {\n if (transpilationRequiredForAllLaterModes) {\n requiresTranspilation[modeName] = true;\n } else if (isSupported()) {\n transpilationTarget = modeName;\n requiresTranspilation[modeName] = false;\n } else {\n requiresTranspilation[modeName] = true;\n transpilationRequiredForAllLaterModes = true;\n }\n }\n\n /**\n * Does the given code evaluate without syntax errors and return a truthy\n * result?\n */\n function /** boolean */ evalCheck(/** string */ code) {\n try {\n return !!eval(code);\n } catch (ignored) {\n return false;\n }\n }\n\n var userAgent = goog.global.navigator && goog.global.navigator.userAgent ?\n goog.global.navigator.userAgent :\n '';\n\n // Identify ES3-only browsers by their incorrect treatment of commas.\n addNewerLanguageTranspilationCheck('es5', function() {\n return evalCheck('[1,].length==1');\n });\n addNewerLanguageTranspilationCheck('es6', function() {\n // Edge has a non-deterministic (i.e., not reproducible) bug with ES6:\n // https://github.com/Microsoft/ChakraCore/issues/1496.\n var re = /Edge\\/(\\d+)(\\.\\d)*/i;\n var edgeUserAgent = userAgent.match(re);\n if (edgeUserAgent) {\n // The Reflect.construct test below is flaky on Edge. It can sometimes\n // pass or fail on 40 15.15063, so just exit early for Edge and treat\n // it as ES5. Until we're on a more up to date version just always use\n // ES5. See https://github.com/Microsoft/ChakraCore/issues/3217.\n return false;\n }\n // Test es6: [FF50 (?), Edge 14 (?), Chrome 50]\n // (a) default params (specifically shadowing locals),\n // (b) destructuring, (c) block-scoped functions,\n // (d) for-of (const), (e) new.target/Reflect.construct\n var es6fullTest =\n 'class X{constructor(){if(new.target!=String)throw 1;this.x=42}}' +\n 'let q=Reflect.construct(X,[],String);if(q.x!=42||!(q instanceof ' +\n 'String))throw 1;for(const a of[2,3]){if(a==2)continue;function ' +\n 'f(z={a}){let a=0;return z.a}{function f(){return 0;}}return f()' +\n '==3}';\n\n return evalCheck('(()=>{\"use strict\";' + es6fullTest + '})()');\n });\n // ** and **= are the only new features in 'es7'\n addNewerLanguageTranspilationCheck('es7', function() {\n return evalCheck('2 ** 2 == 4');\n });\n // async functions are the only new features in 'es8'\n addNewerLanguageTranspilationCheck('es8', function() {\n return evalCheck('async () => 1, true');\n });\n addNewerLanguageTranspilationCheck('es9', function() {\n return evalCheck('({...rest} = {}), true');\n });\n addNewerLanguageTranspilationCheck('es_next', function() {\n return false; // assume it always need to transpile\n });\n return {target: transpilationTarget, map: requiresTranspilation};\n };\n\n\n /**\n * Determines whether the given language needs to be transpiled.\n * @param {string} lang\n * @param {string|undefined} module\n * @return {boolean}\n */\n goog.Transpiler.prototype.needsTranspile = function(lang, module) {\n if (goog.TRANSPILE == 'always') {\n return true;\n } else if (goog.TRANSPILE == 'never') {\n return false;\n } else if (!this.requiresTranspilation_) {\n var obj = this.createRequiresTranspilation_();\n this.requiresTranspilation_ = obj.map;\n this.transpilationTarget_ = this.transpilationTarget_ || obj.target;\n }\n if (lang in this.requiresTranspilation_) {\n if (this.requiresTranspilation_[lang]) {\n return true;\n } else if (\n goog.inHtmlDocument_() && module == 'es6' &&\n !('noModule' in goog.global.document.createElement('script'))) {\n return true;\n } else {\n return false;\n }\n } else {\n throw new Error('Unknown language mode: ' + lang);\n }\n };\n\n\n /**\n * Lazily retrieves the transpiler and applies it to the source.\n * @param {string} code JS code.\n * @param {string} path Path to the code.\n * @return {string} The transpiled code.\n */\n goog.Transpiler.prototype.transpile = function(code, path) {\n // TODO(johnplaisted): We should delete goog.transpile_ and just have this\n // function. But there's some compile error atm where goog.global is being\n // stripped incorrectly without this.\n return goog.transpile_(code, path, this.transpilationTarget_);\n };\n\n\n /** @private @final {!goog.Transpiler} */\n goog.transpiler_ = new goog.Transpiler();\n\n /**\n * Rewrites closing script tags in input to avoid ending an enclosing script\n * tag.\n *\n * @param {string} str\n * @return {string}\n * @private\n */\n goog.protectScriptTag_ = function(str) {\n return str.replace(/<\\/(SCRIPT)/ig, '\\\\x3c/$1');\n };\n\n\n /**\n * A debug loader is responsible for downloading and executing javascript\n * files in an unbundled, uncompiled environment.\n *\n * This can be custimized via the setDependencyFactory method, or by\n * CLOSURE_IMPORT_SCRIPT/CLOSURE_LOAD_FILE_SYNC.\n *\n * @struct @constructor @final @private\n */\n goog.DebugLoader_ = function() {\n /** @private @const {!Object