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/modules/audio_coding/neteq/random_vector.h b/modules/audio_coding/neteq/random_vector.h
index 2c6e06c..e8c7ba8 100644
--- a/modules/audio_coding/neteq/random_vector.h
+++ b/modules/audio_coding/neteq/random_vector.h
@@ -11,10 +11,10 @@
 #ifndef MODULES_AUDIO_CODING_NETEQ_RANDOM_VECTOR_H_
 #define MODULES_AUDIO_CODING_NETEQ_RANDOM_VECTOR_H_
 
-#include <string.h>  // size_t
+#include <stddef.h>
+#include <stdint.h>
 
 #include "rtc_base/constructormagic.h"
-#include "typedefs.h"  // NOLINT(build/include)
 
 namespace webrtc {