LayoutTests for writing empty Blob/File/FileList to IndexedDB.

LayoutTests/storage/indexeddb/empty-filesystem-file-expected.txt

+Confirm that IndexedDB can store an empty File from the Filesystem API
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+Got FileSystem:file__0:Temporary
+indexedDB = self.indexedDB || self.webkitIndexedDB || self.mozIndexedDB || self.msIndexedDB || self.OIndexedDB;
+
+dbname = "empty-filesystem-file.html"
+indexedDB.deleteDatabase(dbname)
+indexedDB.open(dbname)
+store = db.createObjectStore('storeName')
+store.put('value', 'key')
+
+testEmptyFile():
+file = window.emptyFile
+
+validateResult(file):
+transaction = db.transaction('storeName', 'readwrite')
+store = transaction.objectStore('storeName')
+store.put(file, 'filekey')
+transaction = db.transaction('storeName', 'readwrite')
+store = transaction.objectStore('storeName')
+request = store.get('filekey')
+PASS event.target.result.size == 0 is true
+PASS successfullyParsed is true
+
+TEST COMPLETE
+