WIP: Compute constant expressions in resolution.

pkg/compiler/lib/src/js_backend/namer.dart

Index: pkg/compiler/lib/src/js_backend/namer.dart
diff --git a/pkg/compiler/lib/src/js_backend/namer.dart b/pkg/compiler/lib/src/js_backend/namer.dart
index 5bb88de8ea935cdcd98a1f62080bc94c0619ee01..0ff3650c2422d62390445679154d24786ed45bff 100644
--- a/pkg/compiler/lib/src/js_backend/namer.dart
+++ b/pkg/compiler/lib/src/js_backend/namer.dart
@@ -1650,6 +1650,11 @@ class ConstantNamingVisitor implements ConstantValueVisitor {
   }
 
   @override
+  void visitNonConstant(NonConstantValue constant, [_]) {
+    add('null');
+  }
+
+  @override
   void visitInt(IntConstantValue constant, [_]) {
     // No `addRoot` since IntConstants are always inlined.
     if (constant.primitiveValue < 0) {
@@ -1795,6 +1800,9 @@ class ConstantCanonicalHasher implements ConstantValueVisitor<int, Null> {
   int visitNull(NullConstantValue constant, [_]) => 1;
 
   @override
+  int visitNonConstant(NonConstantValue constant, [_]) => 1;
+
+  @override
   int visitBool(BoolConstantValue constant, [_]) {
     return constant.isTrue ? 2 : 3;
   }