Added additional instruction in the regen.sh script to build the
blueprint_tools and aprotoc in case the regen.sh script fails.
Bug: b/169395325
Test: ./regen.sh
Change-Id: Icb38c907fb47febc17eef1067d06d0588dd0b7ba
Test: Dumped the text formated based metrics file to out dir,
and checked the file.
Bug: b/63815990
Change-Id: Iff476f72a0be74eb53b6b26ef468d11c0f24a404