Cleanup bugs in wrapExpressionAsClosure Fix bug in how setters were handled and filter out 'this' f…

tools/dom/src/native_DOMImplementation.dart

Index: tools/dom/src/native_DOMImplementation.dart
diff --git a/tools/dom/src/native_DOMImplementation.dart b/tools/dom/src/native_DOMImplementation.dart
index 2a063c0f491e188066d7cad1a7b6f1d6f5388473..65e117b44a35163a0e5c4ad992d8993be92c4630 100644
--- a/tools/dom/src/native_DOMImplementation.dart
+++ b/tools/dom/src/native_DOMImplementation.dart
@@ -15,6 +15,8 @@ class _ConsoleVariables {
     if (invocation.isGetter) {
       return _data[member];
     } else if (invocation.isSetter) {
+      assert(member.endsWith('='));
+      member = member.substring(0, member.length - 1);
       _data[member] = invocation.positionalArguments[0];
     } else {
       return Function.apply(_data[member], invocation.positionalArguments, invocation.namedArguments);
@@ -133,7 +135,9 @@ class _Utils {
    * expression for a closure with a body matching the original expression
    * where locals are passed in as arguments. Returns a list containing the
    * String expression for the closure and the list of arguments that should
-   * be passed to it.
+   * be passed to it. The expression should then be evaluated using
+   * Dart_EvaluateExpr which will generate a closure that should be invoked
+   * with the list of arguments passed to this method.
    *
    * For example:
    * <code>wrapExpressionAsClosure("foo + bar", ["bar", 40, "foo", 2])</code>
@@ -146,6 +150,12 @@ class _Utils {
     addArg(arg, value) {
       arg = stripMemberName(arg);
       if (args.containsKey(arg)) return;
+      // We ignore arguments with the name 'this' rather than throwing an
+      // exception because Dart_GetLocalVariables includes 'this' and it
+      // is more convenient to filter it out here than from C++ code.
+      // 'this' needs to be handled by calling Dart_EvaluateExpr with
+      // 'this' as the target rather than by passing it as an argument.
+      if (arg == 'this') return;
       if (args.isNotEmpty) {
         sb.write(", ");
       }