Implemented more efficient way to iterate ClassSet in class_hierarchy.dart,
ClassSet becomes Iterable<Class>. This considerably improves speed of
ClosedWorldClassHierarchy.getSingleTargetForInterfaceInvocation() and
CHA-based devirtualization.
Time of CHA-based devirtualization on Flutter Gallery reduced
from ~13.4s to ~1.2s.
Also, ClassHierarchy used in devirtualization is configured to ignore
ambiguous supertypes to avoid crashes on Flutter Gallery.
Change-Id: Iaca251ca268aad3d8bb652247650096f19c25839
Reviewed-on: https://dart-review.googlesource.com/38960
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Alexander Markov
32396138ff