Alphabet Inc.’s Google has entered the glasses race by partnering with Xreal Inc. on the first spectacles to run an augmented-reality version of its operating system. At the Google I/O conference on Tuesday, the search giant and Chinese smart glasses maker showed developers what they call Project Aura, the first eyewear that will run Android XR. The new operating system was announced in December with the goal of mimicking the Android experience on a range of devices. That includes enclosed mixed...