Smartphone sales may be slowing for some tech companies, but not for Apple.Analysts expect another powerhouse performance from the California tech giant when it reports quarterly financial results Tuesday. Apple’s signature iPhones remain popular, even as other smartphone makers are seeing demand slow down.Wall Street analysts estimate Apple will report a hefty $10.3 billion in profit after selling $49 billion worth of iPhones, iPads, Mac computers and other products during the April-June quarter. That’s an increase of more than 30 per cent in both revenue and profit from the same period a year earlier.Apple has said it won’t release sales figures for the new Apple Watch, though some analysts believe demand has fallen since Apple introduced the wearable gadget three months ago. But it almost doesn’t matter: As in other recent quarters, Apple will reap its biggest rewards from its smartphones, especially the new, big-screen iPhone 6 and 6 Plus models introduced last fall.