[CFLAA] Split the CFL graph out from CFLSteens. NFC.

Patch by Jia Chen.

Differential Revision: http://reviews.llvm.org/D21963

llvm-svn: 274591
diff --git a/llvm/lib/Analysis/StratifiedSets.h b/llvm/lib/Analysis/StratifiedSets.h
index 45c317d..b06027a 100644
--- a/llvm/lib/Analysis/StratifiedSets.h
+++ b/llvm/lib/Analysis/StratifiedSets.h
@@ -22,6 +22,7 @@
 #include <vector>
 
 namespace llvm {
+namespace cflaa {
 /// An index into Stratified Sets.
 typedef unsigned StratifiedIndex;
 /// NOTE: ^ This can't be a short -- bootstrapping clang has a case where
@@ -644,4 +645,5 @@
   bool inbounds(StratifiedIndex N) const { return N < Links.size(); }
 };
 }
+}
 #endif // LLVM_ADT_STRATIFIEDSETS_H