Fixed debugger stacktrace generation that failed a VM assertion.

runtime/vm/debugger.cc

 // Copyright (c) 2012, 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/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 867 matching lines @@
   StackFrame* frame = iterator.NextFrame();
   bool get_saved_context = false;
   while (frame != NULL) {
     ASSERT(frame->IsValid());
     if (frame->IsDartFrame()) {
       code = frame->LookupDartCode();
       ActivationFrame* activation = new ActivationFrame(frame->pc(),
                                                         frame->fp(),
                                                         frame->sp(),
                                                         code);
-      if (get_saved_context) {
+      if (get_saved_context && !activation->code().is_optimized()) {
         ctx = activation->GetSavedContext();
       }
       activation->SetContext(ctx);
       stack_trace->AddActivation(activation);
       get_saved_context = activation->function().IsClosureFunction();
     } else if (frame->IsEntryFrame()) {
       ctx = reinterpret_cast<EntryFrame*>(frame)->SavedContext();
       get_saved_context = false;
     }
     frame = iterator.NextFrame();
@@ skipping 835 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart