Make the Expression Execution result enum available to the SB API layer.

Add a callback that will allow an expression to be cancelled between the
expression evaluation stages (for the ClangUserExpressions.)

<rdar://problem/16790467>, <rdar://problem/16573440>

llvm-svn: 207944

lldb/source/API/SBFrame.cpp

@@ -1372,7 +1372,7 @@ SBFrame::EvaluateExpression (const char *expr, const SBExpressionOptions &option
 
     Log *expr_log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
 
-    ExecutionResults exe_results = eExecutionSetupError;
+    ExpressionResults exe_results = eExecutionSetupError;
     SBValue expr_result;
 
     if (expr == NULL || expr[0] == '\0')