Evaluate constant instance creation expressions in ConstantValueComputer.
Evaluate constant instance creation expressions in ConstantValueComputer.

Previously, we evaluated them in ConstantVisitor; as a result we
couldn't take advantage of the ConstantValueComputer's depedendency
graph, so we couldn't detect cycles involving constant constructor
declarations.  This will become important soon, when we expand our
constant evaluation logic to traverse constructor field initializers.

With this change, ConstantValueComputer stores the computed value of
each constant instance creation expression in the AST (similar to how
it stores the computed value of each constant variable in the element
model), and ConstantVisitor simply looks up the already-computed
value.

R=brianwilkerson@google.com

Review URL: https://codereview.chromium.org//270813004

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@35969 260f80e4-7a28-3924-810f-c04153c831b5

dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk