IndexedDB: Use [Default] in IDLs to reduce overloads in implementations

LayoutTests/storage/indexeddb/optional-arguments-expected.txt

+Exercise optional arguments with missing vs. undefined in IndexedDB methods.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+indexedDB = self.indexedDB || self.webkitIndexedDB || self.mozIndexedDB || self.msIndexedDB || self.OIndexedDB;
+
+dbname = "optional-arguments.html"
+indexedDB.deleteDatabase(dbname)
+indexedDB.open(dbname)
+
+prepareDatabase():
+db = event.target.result
+store = db.createObjectStore('store', {keyPath: 'id'})
+store.createIndex('by_name', 'name', {unique: true})
+store.put({id: 1, name: 'a'})
+tx = db.transaction('store', 'readwrite')
+store = tx.objectStore('store')
+index = store.index('by_name')
+PASS IDBKeyRange.lowerBound(0).lowerOpen is false
+PASS IDBKeyRange.upperBound(0).upperOpen is false
+PASS IDBKeyRange.bound(0, 1).lowerOpen is false
+PASS IDBKeyRange.bound(0, 1).upperOpen is false
+PASS IDBKeyRange.lowerBound(0, undefined).lowerOpen is false
+PASS IDBKeyRange.upperBound(0, undefined).upperOpen is false
+PASS IDBKeyRange.bound(0, 1, undefined, undefined).lowerOpen is false
+PASS IDBKeyRange.bound(0, 1, undefined, undefined).upperOpen is false
+PASS store.add({id: 2, name: 'b'}) did not throw exception.
+PASS store.put({id: 3, name: 'c'}) did not throw exception.
+PASS store.add({id: 4, name: 'd'}, undefined) did not throw exception.
+PASS store.put({id: 5, name: 'e'}, undefined) did not throw exception.
+
+verifyCursor():
+request = store.openCursor()
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 5
+
+verifyCursor():
+request = store.openCursor(null)
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 5
+
+verifyCursor():
+request = store.openCursor(IDBKeyRange.lowerBound(4))
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 2
+
+verifyCursor():
+request = store.openCursor(3)
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 1
+
+verifyCursor():
+request = index.openCursor()
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 5
+
+verifyCursor():
+request = index.openCursor(null)
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 5
+
+verifyCursor():
+request = index.openCursor(IDBKeyRange.lowerBound('b'))
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 4
+
+verifyCursor():
+request = index.openCursor('c')
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 1
+
+verifyCursor():
+request = index.openKeyCursor()
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 5
+
+verifyCursor():
+request = index.openKeyCursor(null)
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 5
+
+verifyCursor():
+request = index.openKeyCursor(IDBKeyRange.lowerBound('b'))
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 4
+
+verifyCursor():
+request = index.openKeyCursor('c')
+cursor = request.result
+PASS cursor.direction is "next"
+PASS continues is 1
+
+verifyCount():
+request = store.count()
+PASS request.result is 5
+
+verifyCount():
+request = store.count(null)
+PASS request.result is 5
+
+verifyCount():
+request = store.count(IDBKeyRange.lowerBound(2))
+PASS request.result is 4
+
+verifyCount():
+request = index.count()
+PASS request.result is 5
+
+verifyCount():
+request = index.count(null)
+PASS request.result is 5
+
+verifyCount():
+request = index.count(IDBKeyRange.lowerBound('b'))
+PASS request.result is 4
+
+continueUndefined():
+request = store.openCursor()
+cursor = request.result
+PASS request.result is non-null.
+PASS cursor.continue(undefined) did not throw exception.
+PASS successfullyParsed is true
+
+TEST COMPLETE
+