Update some third_party/base headers.

- Sync bits.h and compiler_specific.h.
- Delete macros.h.

Change-Id: Idf586cd2ea61bc87ed86829d94ae0d4c5a04eae4
Reviewed-on: https://pdfium-review.googlesource.com/43170
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
diff --git a/third_party/base/bits.h b/third_party/base/bits.h
index cd250ed..3a92b4c 100644
--- a/third_party/base/bits.h
+++ b/third_party/base/bits.h
@@ -10,6 +10,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include <type_traits>
+
 #include "third_party/base/compiler_specific.h"
 #include "third_party/base/logging.h"