Handle js interop members in impact computation.

pkg/compiler/lib/src/native/behavior.dart

Index: pkg/compiler/lib/src/native/behavior.dart
diff --git a/pkg/compiler/lib/src/native/behavior.dart b/pkg/compiler/lib/src/native/behavior.dart
index 0a08d3aaf9f4dac57a074873df7979bef4b0205a..7c2a59b401bb362571646852368b824c9d939499 100644
--- a/pkg/compiler/lib/src/native/behavior.dart
+++ b/pkg/compiler/lib/src/native/behavior.dart
@@ -7,13 +7,14 @@ import '../common/backend_api.dart' show ForeignResolver;
 import '../common/resolution.dart' show ParsingContext, Resolution;
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
-import '../common_elements.dart' show CommonElements;
+import '../common_elements.dart' show CommonElements, ElementEnvironment;
 import '../elements/elements.dart';
 import '../elements/entities.dart';
 import '../elements/resolution_types.dart';
 import '../elements/types.dart';
 import '../js/js.dart' as js;
 import '../js_backend/native_data.dart' show NativeBasicData;
+import '../resolution/resolution_strategy.dart';
 import '../tree/tree.dart';
 import '../universe/side_effects.dart' show SideEffects;
 import '../util/util.dart';
@@ -851,8 +852,7 @@ abstract class BehaviorBuilder {
   DiagnosticReporter get reporter;
   NativeBasicData get nativeBasicData;
   bool get trustJSInteropTypeAnnotations;
-
-  Resolution get resolution => null;
+  ElementEnvironment get elementEnvironment;
 
   NativeBehavior _behavior;
 
@@ -910,10 +910,7 @@ abstract class BehaviorBuilder {
   /// Models the behavior of having instances of [type] escape from Dart code
   /// into native code.
   void _escape(DartType type) {
-    if (type is ResolutionDartType) {
-      type.computeUnaliased(resolution);
-    }
-    type = type.unaliased;
+    type = elementEnvironment.getUnaliasedType(type);
     if (type is FunctionType) {
       FunctionType functionType = type;
       // A function might be called from native code, passing us novel
@@ -932,10 +929,7 @@ abstract class BehaviorBuilder {
   /// We assume that JS-interop APIs cannot instantiate Dart types or
   /// non-JSInterop native types.
   void _capture(DartType type, {bool isInterop: false}) {
-    if (type is ResolutionDartType) {
-      type.computeUnaliased(resolution);
-    }
-    type = type.unaliased;
+    type = elementEnvironment.getUnaliasedType(type);
     if (type is FunctionType) {
       FunctionType functionType = type;
       _capture(functionType.returnType, isInterop: isInterop);
@@ -962,9 +956,8 @@ abstract class BehaviorBuilder {
           // annotations. This means that to some degree we still use the return
           // type to decide whether to include native types, even if we don't
           // trust the type annotation.
-          ClassElement cls = commonElements.jsJavaScriptObjectClass;
-          cls.ensureResolved(resolution);
-          _behavior.typesInstantiated.add(cls.thisType);
+          ClassEntity cls = commonElements.jsJavaScriptObjectClass;
+          _behavior.typesInstantiated.add(elementEnvironment.getThisType(cls));
         } else {
           // Otherwise, when the declared type is a Dart type, we do not
           // register an allocation because we assume it cannot be instantiated
@@ -1040,7 +1033,7 @@ class ResolverBehaviorBuilder extends BehaviorBuilder {
   ResolverBehaviorBuilder(this.compiler, this.nativeBasicData);
 
   @override
-  CommonElements get commonElements => resolution.commonElements;
+  CommonElements get commonElements => compiler.resolution.commonElements;
 
   @override
   bool get trustJSInteropTypeAnnotations =>
@@ -1050,5 +1043,8 @@ class ResolverBehaviorBuilder extends BehaviorBuilder {
   DiagnosticReporter get reporter => compiler.reporter;
 
   @override
-  Resolution get resolution => compiler.resolution;
+  ElementEnvironment get elementEnvironment {
+    ResolutionFrontEndStrategy frontendStrategy = compiler.frontendStrategy;
+    return frontendStrategy.elementEnvironment;
+  }
 }