Delete root header file typedef.h.

Usage replaced with stdint.h, rtc_base/system/arch.h and
rtc_base/system/unused.h, as appropriate.

Bug: webrtc:6854
Change-Id: I97225465d14b969903d92979e2df3c3c05d35f18
Reviewed-on: https://webrtc-review.googlesource.com/90249
Reviewed-by: Niklas Enbom <niklas.enbom@webrtc.org>
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24100}
diff --git a/common_audio/wav_header.cc b/common_audio/wav_header.cc
index d093fa0..8fc5fef 100644
--- a/common_audio/wav_header.cc
+++ b/common_audio/wav_header.cc
@@ -21,6 +21,7 @@
 
 #include "common_audio/include/audio_util.h"
 #include "rtc_base/checks.h"
+#include "rtc_base/system/arch.h"
 
 namespace webrtc {
 namespace {