Make blink::LayoutUnit::HasFraction constexpr

Other HasFraction methods as in PhysicalUnit are declared already
constexpr and using it. It breaks GCC build.

Bug: 819294.
Change-Id: I0c4bd9bd206d45cf31f7fa815ce8533718a425cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1645222
Reviewed-by: vmpstr <vmpstr@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: José Dapena Paz <jose.dapena@lge.com>
Cr-Commit-Position: refs/heads/master@{#666336}
1 file changed