Merge CoreTypes and CoreClasses into CommonElements.

pkg/compiler/lib/src/ssa/kernel_impact.dart

Index: pkg/compiler/lib/src/ssa/kernel_impact.dart
diff --git a/pkg/compiler/lib/src/ssa/kernel_impact.dart b/pkg/compiler/lib/src/ssa/kernel_impact.dart
index 155c10e4681be8e862caa444f12278dfa3fa4f2e..44768509d6a2d4ada544ec005cf36729cdc4243b 100644
--- a/pkg/compiler/lib/src/ssa/kernel_impact.dart
+++ b/pkg/compiler/lib/src/ssa/kernel_impact.dart
@@ -222,7 +222,7 @@ class KernelImpactBuilder extends ir.Visitor {
     DartType elementType = checkType(literal.typeArgument);
 
     impactBuilder.registerListLiteral(new ListLiteralUse(
-        compiler.coreTypes.listType(elementType),
+        compiler.commonElements.listType(elementType),
         isConstant: literal.isConst,
         isEmpty: literal.expressions.isEmpty));
   }
@@ -233,7 +233,7 @@ class KernelImpactBuilder extends ir.Visitor {
     DartType keyType = checkType(literal.keyType);
     DartType valueType = checkType(literal.valueType);
     impactBuilder.registerMapLiteral(new MapLiteralUse(
-        compiler.coreTypes.mapType(keyType, valueType),
+        compiler.commonElements.mapType(keyType, valueType),
         isConstant: literal.isConst,
         isEmpty: literal.entries.isEmpty));
   }