Inline commonly used Error methods and add move operators. The function call overhead of the constructors and assignement operators ended up being a hotspot even though the functions didn't do any significant work. BUG=angleproject:959 Change-Id: I96769879dabdbba7a222f98d87c5be0a829cb7dd Reviewed-on: https://chromium-review.googlesource.com/262335 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Nicolas Capens <capn@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>