Add gdb helper functions for creating a handle and using ToCString with RawObjects.

runtime/lib/object.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/bootstrap_natives.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/code_patcher.h"
 #include "vm/exceptions.h"
 #include "vm/heap.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, trace_type_checks);
 
-// Helper function in stacktrace.cc.
-void _printCurrentStackTrace();
+// Helper function in gdb_helpers.cc.
+void _printDartStackTrace();
 
 DEFINE_NATIVE_ENTRY(DartAsync_fatal, 1) {
   // The dart:async library code entered an unrecoverable state.
   const Instance& instance = Instance::CheckedHandle(arguments->NativeArgAt(0));
   const char* msg = instance.ToCString();
   OS::PrintErr("Fatal error in dart:async: %s\n", msg);
-  _printCurrentStackTrace();
+  _printDartStackTrace();
   FATAL(msg);
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(Object_equals, 1) {
   // Implemented in the flow graph builder.
   UNREACHABLE();
   return Object::null();
 }
@@ skipping 354 matching lines @@
   for (intptr_t i = split; i < len; i++) {
     type = function_type_arguments.IsNull()
                ? Type::DynamicType()
                : function_type_arguments.TypeAt(i - split);
     result.SetTypeAt(i, type);
   }
   return result.Canonicalize();
 }
 
 }  // namespace dart