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/remote_bitrate_estimator/BUILD.gn b/modules/remote_bitrate_estimator/BUILD.gn
index abdd035..1261203 100644
--- a/modules/remote_bitrate_estimator/BUILD.gn
+++ b/modules/remote_bitrate_estimator/BUILD.gn
@@ -40,7 +40,6 @@
 
   deps = [
     "../..:webrtc_common",
-    "../../:typedefs",
     "../../modules:module_api",
     "../../modules/rtp_rtcp:rtp_rtcp_format",
     "../../rtc_base:checks",
@@ -122,7 +121,6 @@
       ":remote_bitrate_estimator",
       "..:module_api",
       "../..:webrtc_common",
-      "../../:typedefs",
       "../../logging:mocks",
       "../../rtc_base:checks",
       "../../rtc_base:gtest_prod",
@@ -132,6 +130,7 @@
       "../../rtc_base:safe_minmax",
       "../../rtc_base/experiments:alr_experiment",
       "../../rtc_base/system:fallthrough",
+      "../../rtc_base/system:unused",
       "../../system_wrappers",
       "../../system_wrappers:field_trial_api",
       "../../test:fileutils",