Fix some clang warnings with -Wmissing-braces in ANGLE. Clang warns if there are missing braces around a subobject initializer. The most common idiom that triggers this is: STRUCT s = {0}; which can be more simply written as: STRUCT s = {}; BUG=505297 Change-Id: Ib4513ee195d43e7c4a4a2f46c328866f0023a2a5 Reviewed-on: https://chromium-review.googlesource.com/282921 Reviewed-by: Kenneth Russell <kbr@chromium.org> Tested-by: Kenneth Russell <kbr@chromium.org>