Fix issue 1857: code lookup was wrong when searching for exception handler.

runtime/vm/stack_frame.h

 // 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.
 
 #ifndef VM_STACK_FRAME_H_
 #define VM_STACK_FRAME_H_
 
 #include "vm/allocation.h"
 #include "vm/object.h"
 #include "vm/stub_code.h"
@@ skipping 114 matching lines @@
  public:
   bool IsValid() const { return (LookupDartFunction() != Function::null()); }
   bool IsDartFrame() const { return true; }
 
   // Visit objects in the frame.
   virtual void VisitObjectPointers(ObjectPointerVisitor* visitor);
 
   // Get function object corresponding to pc for the frame.
   RawFunction* LookupDartFunction() const;
 
+  // Get code object corresponding to pc for the frame.
+  RawCode* LookupDartCode() const;
+
   // Find exception handler pc in frame if one exists.
   bool FindExceptionHandler(uword* handler_pc) const;
 
  protected:
   virtual const char* GetName() const { return "dart"; }
 
  private:
   DartFrame() { }
 
   friend class StackFrameIterator;
@@ skipping 110 matching lines @@
 
  private:
   StackFrameIterator frames_;
 
   DISALLOW_COPY_AND_ASSIGN(DartFrameIterator);
 };
 
 }  // namespace dart
 
 #endif  // VM_STACK_FRAME_H_