Fix source location of mixins in stack trace

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 221 matching lines @@
   return script.url();
 }
 
 
 RawScript* ActivationFrame::SourceScript() {
   return function().script();
 }
 
 
 RawLibrary* ActivationFrame::Library() {
-  const Class& cls = Class::Handle(function().Owner());
+  const Class& cls = Class::Handle(function().origin());
   return cls.library();
 }
 
 
 void ActivationFrame::GetPcDescriptors() {
   if (pc_desc_.IsNull()) {
     pc_desc_ = code().pc_descriptors();
     ASSERT(!pc_desc_.IsNull());
   }
 }
@@ skipping 1987 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart