Print stack trace when Dart_SetReturnValue is passed UnwindError.

runtime/lib/stacktrace.cc

 // Copyright (c) 2013, 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 "lib/stacktrace.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/exceptions.h"
 #include "vm/object_store.h"
 #include "vm/runtime_entry.h"
 #include "vm/stack_frame.h"
 
 namespace dart {
 
 static void IterateFrames(const GrowableObjectArray& code_list,
                           const GrowableObjectArray& pc_offset_list,
@@ skipping 14 matching lines @@
         pc_offset_list.Add(offset);
       }
     }
     frame = frames.NextFrame();
   }
 }
 
 // Creates a Stacktrace object from the current stack.
 //
 // Skips the first skip_frames Dart frames.
-static const Stacktrace& GetCurrentStacktrace(int skip_frames) {
+const Stacktrace& GetCurrentStacktrace(int skip_frames) {
   const GrowableObjectArray& code_list =
       GrowableObjectArray::Handle(GrowableObjectArray::New());
   const GrowableObjectArray& pc_offset_list =
       GrowableObjectArray::Handle(GrowableObjectArray::New());
   IterateFrames(code_list, pc_offset_list, skip_frames);
   const Array& code_array = Array::Handle(Array::MakeArray(code_list));
   const Array& pc_offset_array =
       Array::Handle(Array::MakeArray(pc_offset_list));
   const Stacktrace& stacktrace = Stacktrace::Handle(
       Stacktrace::New(code_array, pc_offset_array));
   return stacktrace;
 }
 
 // An utility method for convenient printing of dart stack traces when
 // inside 'gdb'. Note: This function will only work when there is a
 // valid exit frame information. It will not work when a breakpoint is
 // set in dart code and control is got inside 'gdb' without going through
 // the runtime or native transition stub.
 void _printCurrentStacktrace() {
   const Stacktrace& stacktrace = GetCurrentStacktrace(0);
   OS::PrintErr("=== Current Trace:\n%s===\n", stacktrace.ToCString());
 }
 
 DEFINE_NATIVE_ENTRY(StackTrace_current, 0) {
   const Stacktrace& stacktrace = GetCurrentStacktrace(1);
   return stacktrace.raw();
 }
 
 }  // namespace dart