Implement handlified String::Equals and Name::Equals.

src/ast.cc

Index: src/ast.cc
diff --git a/src/ast.cc b/src/ast.cc
index b522c98b9a186ebf6ffdccb230336335ddfb98bb..b9e0b38561868236174684e3c39b80cdf9ec935e 100644
--- a/src/ast.cc
+++ b/src/ast.cc
@@ -78,7 +78,8 @@ bool Expression::IsUndefinedLiteral(Isolate* isolate) const {
   // The global identifier "undefined" is immutable. Everything
   // else could be reassigned.
   return var != NULL && var->location() == Variable::UNALLOCATED &&
-         var_proxy->name()->Equals(isolate->heap()->undefined_string());
+         String::Equals(var_proxy->name(),
+                        isolate->factory()->undefined_string());
 }
 
 
@@ -207,9 +208,10 @@ ObjectLiteralProperty::ObjectLiteralProperty(
   emit_store_ = true;
   key_ = key;
   value_ = value;
-  Object* k = *key->value();
+  Handle<Object> k = key->value();
   if (k->IsInternalizedString() &&
-      zone->isolate()->heap()->proto_string()->Equals(String::cast(k))) {
+      String::Equals(Handle<String>::cast(k),
+                     zone->isolate()->factory()->proto_string())) {
     kind_ = PROTOTYPE;
   } else if (value_->AsMaterializedLiteral() != NULL) {
     kind_ = MATERIALIZED_LITERAL;