President Trump on Friday is expected to sign an executive order that could open large parts of the Pacific, Arctic and Atlantic oceans to new oil and gas drilling, a prospect that elicited a fierce backlash in California and elsewhere even before details of the order were clear. The move, which is certain to face legal and political challenges, could undo a plan finalized late in President Obama’s second term that sought to limit fossil fuel development and fight climate change by not including new drilling leases off the coast of California or Alaska during the current five-year federal offshore...