Add ScopeInfo class for variable information that doesn't actually involve closures.

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

Index: pkg/compiler/lib/src/kernel/closure.dart
diff --git a/pkg/compiler/lib/src/kernel/closure.dart b/pkg/compiler/lib/src/kernel/closure.dart
index 9354ae3c29280f351abcde25a64792e1cb9b5ab2..b8b9467c51177088f2593a1fc92621ed7406c04a 100644
--- a/pkg/compiler/lib/src/kernel/closure.dart
+++ b/pkg/compiler/lib/src/kernel/closure.dart
@@ -44,14 +44,14 @@ class KernelClosureDataBuilder extends ir.Visitor {
   @override
   visitVariableGet(ir.VariableGet node) {
     if (_inTry) {
-      info.registerUsedInTryOrSync(_localsMap.getLocal(node.variable));
+      info.variablesUsedInTryOrSync.add(_localsMap.getLocal(node.variable));
     }
   }
 
   @override
   visitVariableSet(ir.VariableSet node) {
     if (_inTry) {
-      info.registerUsedInTryOrSync(_localsMap.getLocal(node.variable));
+      info.variablesUsedInTryOrSync.add(_localsMap.getLocal(node.variable));
     }
     node.visitChildren(this);
   }
@@ -104,6 +104,12 @@ class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
     return const LoopClosureRepresentationInfo();
   }
 
+  @override
+  ScopeInfo getScopeInfo(Entity entity) {
+    // TODO(efortuna): Specialize this function from the one below.
+    return getClosureRepresentationInfo(entity);
+  }
+
   @override
   ClosureRepresentationInfo getClosureRepresentationInfo(Entity entity) {
     return _infoMap.putIfAbsent(entity, () {
@@ -129,21 +135,15 @@ class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
 // [ClosureRepresentationInfo].
 class KernelClosureRepresentationInfo extends ClosureRepresentationInfo {
   final ThisLocal thisLocal;
-  final Set<Local> _localsUsedInTryOrSync = new Set<Local>();
+  final Set<Local> variablesUsedInTryOrSync = new Set<Local>();
 
   KernelClosureRepresentationInfo(this.thisLocal);
 
-  void registerUsedInTryOrSync(Local local) {
-    _localsUsedInTryOrSync.add(local);
-  }
-
-  bool variableIsUsedInTryOrSync(Local variable) =>
-      _localsUsedInTryOrSync.contains(variable);
-
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.write('this=$thisLocal,');
-    sb.write('localsUsedInTryOrSync={${_localsUsedInTryOrSync.join(', ')}}');
+    sb.write(
+        'variablesUsedInTryOrSync={${variablesUsedInTryOrSync.join(', ')}}');
     return sb.toString();
   }
 }