Upstream service worker indexedDB tests to WPT

third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/indexeddb-worker.js

-self.addEventListener('message', function(e) {
-    var message = e.data;
-    if ('port' in message)
-      e.waitUntil(doIndexedDBTest(message.port));
-  });
-
-function doIndexedDBTest(port) {
-  return new Promise(function(resolve) {
-    var delete_request = indexedDB.deleteDatabase('db');
-    delete_request.onsuccess = function() {
-      var open_request = indexedDB.open('db');
-      open_request.onupgradeneeded = function() {
-        var db = open_request.result;
-        db.createObjectStore('store');
-      };
-      open_request.onsuccess = function() {
-        var db = open_request.result;
-        var tx = db.transaction('store', 'readwrite');
-        var store = tx.objectStore('store');
-        store.put('value', 'key');
-        tx.oncomplete = function() {
-          port.postMessage('done');
-          resolve();
-        };
-      };
-    };
-  });
-}