Qualcomm Inc. and Arm Holdings Plc, two chip companies heavily dependent on the smartphone market, delivered earnings reports Wednesday that showed an industry making a wobbly comeback. Both companies pointed to a resurgence in demand for high-end model devices, but stopped short of signaling that the broader industry was on solid ground. Qualcomm’s report was better received, with a rosy sales forecast helping send its shares up in late trading. A more tentative Arm outlook, meanwhile, weighed ...