Add boxed fields in closure classes.

pkg/compiler/lib/src/kernel/element_map_impl.dart

Index: pkg/compiler/lib/src/kernel/element_map_impl.dart
diff --git a/pkg/compiler/lib/src/kernel/element_map_impl.dart b/pkg/compiler/lib/src/kernel/element_map_impl.dart
index da6e337738f1c799d51464858231d81e5f361d50..2e56e4639c057a2bae628c3ddee3192b6d56295e 100644
--- a/pkg/compiler/lib/src/kernel/element_map_impl.dart
+++ b/pkg/compiler/lib/src/kernel/element_map_impl.dart
@@ -6,6 +6,7 @@ library dart2js.kernel.element_map;
 
 import 'package:kernel/ast.dart' as ir;
 
+import '../closure.dart' show BoxLocal;
 import '../common.dart';
 import '../common/names.dart' show Identifiers;
 import '../common/resolution.dart';
@@ -1996,8 +1997,8 @@ class JsKernelToElementMap extends KernelToElementMapBase
       KernelToLocalsMap localsMap,
       InterfaceType supertype) {
     String name = _computeClosureName(node);
-    KernelClosureClass cls = new KernelClosureClass.fromScopeInfo(
-        name, _classEnvs.length, enclosingLibrary, info, location, localsMap);
+    KernelClosureClass cls = new KernelClosureClass.fromScopeInfo(node, name,
+        _classEnvs.length, enclosingLibrary, info, location, localsMap);
     _classList.add(cls);
     _classEnvs.add(new ClassEnv.closureClass());
 
@@ -2020,7 +2021,8 @@ class JsKernelToElementMap extends KernelToElementMapBase
     for (ir.VariableDeclaration variable in info.freeVariables) {
       // Make a corresponding field entity in this closure class for every
       // single freeVariable in the KernelScopeInfo.freeVariable.
-      _constructClosureFields(cls, variable, i, localsMap);
+      _constructClosureFields(
+          cls, variable, i, info.capturedVariablesAccessor, localsMap);
       i++;
     }
 
@@ -2039,13 +2041,29 @@ class JsKernelToElementMap extends KernelToElementMapBase
       KernelClosureClass cls,
       ir.VariableDeclaration variable,
       int fieldNumber,
+      NodeBox box,
       KernelToLocalsMap localsMap) {
     // NOTE: This construction order may be slightly different than the
     // old Element version. The old version did all the boxed items and then
     // all the others.
     Local capturedLocal = localsMap.getLocalVariable(variable);
     if (cls.isBoxed(capturedLocal)) {
-      // TODO(efortuna): Coming soon.
+      var boxedField = new JBoxedField(
+          _getClosureVariableName(capturedLocal.name, fieldNumber),
+          _memberData.length,
+          new BoxLocal(
+              box.name,
+              localsMap.getLocalVariable(box.executableContext),

[Johnni Winther, 2017/08/01 09:09:10]

The `Local.executableContext` is actually not needed after closure translation.
I'll remove it when you're done with the closure conversion.

[Emily Fortuna, 2017/08/01 19:30:06]

Acknowledged.

+              getMember(box.memberContext)),

[Johnni Winther, 2017/08/01 09:09:10]

The member is always the member passed to [constructClosureClass], just use this
here and avoid the need for memberContext computation.

[Emily Fortuna, 2017/08/01 19:30:06]

Done.

+          cls,
+          variable.isConst,
+          variable.isFinal || variable.isConst);
+      cls.localToFieldMap[capturedLocal] = boxedField;
+      _memberList.add(boxedField);
+      _memberData.add(new MemberData(
+          null,
+          new ClosureMemberDefinition(boxedField, variable.location,
+              MemberKind.closureField, variable)));
     } else {
       var closureField = new JClosureField(
           _getClosureVariableName(capturedLocal.name, fieldNumber),