Import wpt@cf62b859e6b890abc34f8140d185ba91df95c5b6

third_party/WebKit/LayoutTests/external/wpt/common/vendor-prefix.js

-/* Use this script when you want to test APIs that use vendor prefixes
-   and define which objects need to be checked for prefixed versions, à la
-   <script src="vendor-prefix.js"
-     data-prefixed-objects='[{"ancestors":["navigator"], "name":"getUserMedia"}]'
-   data-prefixed-prototypes='[{"ancestors":["HTMLMediaElement"],"name":"srcObject"}]'></script>
-   data-prefixed-objects lets prefix objects in the global space
-   data-prefixed-prototypes adds prefixes to interfaces, for objects that
-   get created during the tests
-
-   NB: vendor prefixes are expected to go away in favor of putting
-   new features behind flag, so hopefully there will be only limited
-   need to use this
-*/
-
-(function () {
-    var aliases = {};
-    var documentingPrefixUsage = document.createElement('div');
-    var vendorPrefixes = ["moz", "ms", "o", "webkit", "Moz", "MS", "O", "WebKit", "op"];
-
-    function getParentObject(ancestors) {
-        var parent = window;
-        var currentName = "";
-        ancestors.forEach(function (p) {
-            currentName = currentName ? currentName + "." + p : p;
-            if (parent[p] === undefined) {
-                throw currentName + " is undefined, cannot set prefix alias on child object";
-            }
-            parent = parent[p];
-        });
-        return parent;
-    }
-
-    function prependPrefix(prefix, name) {
-        var newName = name[0].toUpperCase() + name.substr(1, name.length);
-        return prefix + newName;
-    }
-
-    function setPrototypeAlias(obj) {
-        var parent = getParentObject(obj.ancestors);
-        if (!parent.prototype.hasOwnProperty(obj.name)) {
-            vendorPrefixes.forEach(function (prefix) {
-                if (parent.prototype.hasOwnProperty(prependPrefix(prefix, obj.name))) {
-                    Object.defineProperty(parent.prototype, obj.name,
-                                          {get: function() {return this[prependPrefix(prefix, obj.name)];},
-                                           set: function(v) {this[prependPrefix(prefix, obj.name)] = v;}
-                                          });
-                    aliases[obj.ancestors.join(".") + ".prototype." + obj.name] = obj.ancestors.join(".") + ".prototype." + prependPrefix(prefix, obj.name);
-                    return;
-                }
-            });
-        }
-    }
-
-    function setAlias(obj) {
-        var parent = getParentObject(obj.ancestors);
-        if (parent[obj.name] === undefined) {
-            vendorPrefixes.forEach(function (prefix) {
-                if (parent[prependPrefix(prefix, obj.name)] !== undefined) {
-                    parent[obj.name] = parent[prependPrefix(prefix, obj.name)];
-                    aliases[obj.ancestors.join(".") + "." + obj.name] = obj.ancestors.join(".") + "." + prependPrefix(prefix, obj.name);
-                    return;
-                }
-            });
-        }
-    }
-
-    if (location.search.indexOf('usePrefixes=1') !== -1) {
-        if (document.querySelector("script[data-prefixed-objects]")) {
-            var prefixObjectsData = document.querySelector("script[data-prefixed-objects]").dataset["prefixedObjects"];
-            try {
-                var prefixedObjects = JSON.parse(prefixObjectsData);
-            } catch (e) {
-                throw "couldn't parse data-prefixed-objects as JSON:" + e;
-            }
-            prefixedObjects.forEach(setAlias);
-        }
-        if (document.querySelector("script[data-prefixed-prototypes]")) {
-            var prefixProtoData = document.querySelector("script[data-prefixed-prototypes]").dataset["prefixedPrototypes"];
-            try {
-                var prefixedPrototypes = JSON.parse(prefixProtoData);
-            } catch (e) {
-                throw "couldn't parse data-prefixed-prototypes as JSON:" + e;
-            }
-            prefixedPrototypes.forEach(setPrototypeAlias);
-        }
-        var ul = document.createElement("ul");
-        Object.keys(aliases).forEach(function (alias) {
-            var li = document.createElement("li");
-            li.appendChild(document.createTextNode(alias + " has been set to be an alias of vendor-prefixed " + aliases[alias]));
-            ul.appendChild(li);
-        });
-        documentingPrefixUsage.appendChild(ul);
-    } else {
-        // Document that the test can be run with prefixes enabled
-
-        var a = document.createElement('a');
-        var link = "";
-        if (location.search) {
-            link = location.search + "&usePrefixes=1";
-        } else {
-            link = "?usePrefixes=1";
-        }
-        a.setAttribute("href", link);
-        a.appendChild(document.createTextNode("with vendor prefixes enabled"));
-        documentingPrefixUsage.appendChild(document.createTextNode("The feature(s) tested here are known to have been made available via vendor prefixes; you can run this test "));
-        documentingPrefixUsage.appendChild(a);
-        documentingPrefixUsage.appendChild(document.createTextNode("."));
-    }
-    var log = document.getElementById('log');
-    if (log) {
-        log.parentNode.insertBefore(documentingPrefixUsage, log);
-    } else {
-        document.body.appendChild(documentingPrefixUsage);
-    }
-})();