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/codecs/opus/opus_interface.h b/modules/audio_coding/codecs/opus/opus_interface.h
index 0b1c64d..ddb4ff9 100644
--- a/modules/audio_coding/codecs/opus/opus_interface.h
+++ b/modules/audio_coding/codecs/opus/opus_interface.h
@@ -12,9 +12,9 @@
 #define MODULES_AUDIO_CODING_CODECS_OPUS_OPUS_INTERFACE_H_
 
 #include <stddef.h>
+#include <stdint.h>
 
 #include "modules/audio_coding/codecs/opus/opus_inst.h"
-#include "typedefs.h"  // NOLINT(build/include)
 
 #ifdef __cplusplus
 extern "C" {