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/Commands/CommandObjectExpression.cpp b/lldb/source/Commands/CommandObjectExpression.cpp
index 89edf42..8b04da6 100644
--- a/lldb/source/Commands/CommandObjectExpression.cpp
+++ b/lldb/source/Commands/CommandObjectExpression.cpp
@@ -32,7 +32,7 @@
 #include "lldb/Symbol/ObjectFile.h"
 #include "lldb/Symbol/Variable.h"
 #include "lldb/Target/Process.h"
-#include "lldb/Target/Frame.h"
+#include "lldb/Target/StackFrame.h"
 #include "lldb/Target/Target.h"
 #include "lldb/Target/Thread.h"
 #include "llvm/ADT/StringRef.h"