Polymer 2.0 is production ready, and we advise all projects to
begin migration. To aid in that migration, we're writing and
applying some automated fixes for the mechanical parts of
the upgrade.
This change migrates uses of @apply to remove the deprecated
parentheses syntax, and adds var() to use of CSS Custom
Properties in the fallback position of a var() expression.
These changes are backwards-compatible with Polymer 1.0
applications, as well as browser-native implementations
of CSS Custom Properties.
Change-Id: I03139145e661afa43830015a33d38080d936cd6f
e1e8599968