Roll back the changes I made in r193907 which created a new Frame
pure virtual base class and made StackFrame a subclass of that.  As
I started to build on top of that arrangement today, I found that it
wasn't working out like I intended.  Instead I'll try sticking with
the single StackFrame class -- there's too much code duplication to
make a more complicated class hierarchy sensible I think.

llvm-svn: 193983
diff --git a/lldb/source/Core/ValueObjectVariable.cpp b/lldb/source/Core/ValueObjectVariable.cpp
index f0e88e6..3d8b07a 100644
--- a/lldb/source/Core/ValueObjectVariable.cpp
+++ b/lldb/source/Core/ValueObjectVariable.cpp
@@ -263,7 +263,7 @@
     if (exe_ctx_ref.HasFrameRef())
     {
         ExecutionContext exe_ctx (exe_ctx_ref);
-        Frame *frame = exe_ctx.GetFramePtr();
+        StackFrame *frame = exe_ctx.GetFramePtr();
         if (frame)
         {
             return m_variable_sp->IsInScope (frame);