Move a method from IdentifierTable.h out of line and remove the SmallString include.

Fix all the transitive include users.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149783 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index d102fb3..e1a1150 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -18,6 +18,7 @@
 #include "clang/Sema/Scope.h"
 #include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/PrettyDeclStackTrace.h"
+#include "llvm/ADT/SmallString.h"
 #include "RAIIObjectsForParser.h"
 using namespace clang;