FormatInternal.h: Add missing includes.

llvm-svn: 318719
diff --git a/clang/lib/Format/FormatInternal.h b/clang/lib/Format/FormatInternal.h
index 1373e9d..3984158 100644
--- a/clang/lib/Format/FormatInternal.h
+++ b/clang/lib/Format/FormatInternal.h
@@ -16,6 +16,10 @@
 #ifndef LLVM_CLANG_LIB_FORMAT_FORMATINTERNAL_H
 #define LLVM_CLANG_LIB_FORMAT_FORMATINTERNAL_H
 
+#include "BreakableToken.h"
+#include "clang/Tooling/Core/Lookup.h"
+#include <utility>
+
 namespace clang {
 namespace format {
 namespace internal {