Convert ARRAYSIZE_UNSAFE -> arraysize in base/.

R=thestig@chromium.org
BUG=423134

Review URL: https://codereview.chromium.org/656033009

Cr-Commit-Position: refs/heads/master@{#299835}
void WarmUpBacktrace() {
  StackTrace stack_trace;
}

void WarmUpBacktrace() {
  StackTrace stack_trace;
}
