Prefix resolution_types with Resolution.

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

Index: pkg/compiler/lib/src/js_backend/checked_mode_helpers.dart
diff --git a/pkg/compiler/lib/src/js_backend/checked_mode_helpers.dart b/pkg/compiler/lib/src/js_backend/checked_mode_helpers.dart
index 7091dc677e0c6d60fc1fc9d8651f0112cfd180d9..818f82c4b6e320e2b0b21e34aecd44bccbdf0808 100644
--- a/pkg/compiler/lib/src/js_backend/checked_mode_helpers.dart
+++ b/pkg/compiler/lib/src/js_backend/checked_mode_helpers.dart
@@ -104,7 +104,7 @@ class PropertyCheckedModeHelper extends CheckedModeHelper {
 
   void generateAdditionalArguments(SsaCodeGenerator codegen,
       HTypeConversion node, List<jsAst.Expression> arguments) {
-    DartType type = node.typeExpression;
+    ResolutionDartType type = node.typeExpression;
     jsAst.Name additionalArgument = codegen.backend.namer.operatorIsType(type);
     arguments.add(js.quoteName(additionalArgument));
   }
@@ -130,7 +130,7 @@ class SubtypeCheckedModeHelper extends CheckedModeHelper {
 
   void generateAdditionalArguments(SsaCodeGenerator codegen,
       HTypeConversion node, List<jsAst.Expression> arguments) {
-    DartType type = node.typeExpression;
+    ResolutionDartType type = node.typeExpression;
     Element element = type.element;
     jsAst.Name isField = codegen.backend.namer.operatorIs(element);
     arguments.add(js.quoteName(isField));