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}

modules/video_processing/BUILD.gn

@@ -32,6 +32,7 @@ rtc_static_library("video_processing") {
     "../../modules/utility",
     "../../rtc_base:checks",
     "../../rtc_base:rtc_base_approved",
+    "../../rtc_base/system:arch",
     "../../system_wrappers:cpu_features_api",
     "//third_party/libyuv",
   ]

modules/video_processing/util/denoiser_filter.cc

@@ -13,6 +13,7 @@
 #include "modules/video_processing/util/denoiser_filter_neon.h"
 #include "modules/video_processing/util/denoiser_filter_sse2.h"
 #include "rtc_base/checks.h"
+#include "rtc_base/system/arch.h"
 #include "system_wrappers/include/cpu_features_wrapper.h"
 
 namespace webrtc {