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/sdk/objc/Framework/UnitTests/RTCPeerConnectionFactoryBuilderTest.mm b/sdk/objc/Framework/UnitTests/RTCPeerConnectionFactoryBuilderTest.mm
index fa78aed..b09cc12 100644
--- a/sdk/objc/Framework/UnitTests/RTCPeerConnectionFactoryBuilderTest.mm
+++ b/sdk/objc/Framework/UnitTests/RTCPeerConnectionFactoryBuilderTest.mm
@@ -28,6 +28,7 @@
 #include "modules/audio_processing/include/audio_processing.h"
 
 #include "rtc_base/gunit.h"
+#include "rtc_base/system/unused.h"
 
 @interface RTCPeerConnectionFactoryBuilderTest : NSObject
 - (void)testBuilder;