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/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index 7f9d834..f4b89dd 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -109,6 +109,9 @@
     "stringize_macros.h",
     "thread_annotations.h",
   ]
+  deps = [
+    "system:arch",
+  ]
 }
 
 rtc_source_set("platform_thread_types") {
@@ -150,7 +153,7 @@
     ":checks",
     ":macromagic",
     ":platform_thread_types",
-    "..:typedefs",
+    "system:unused",
   ]
 }
 
@@ -174,7 +177,6 @@
     ":rtc_event",
     ":thread_checker",
     ":timeutils",
-    "..:typedefs",
   ]
 }
 
@@ -239,7 +241,6 @@
     ":criticalsection",
     ":macromagic",
     ":platform_thread_types",
-    "..:typedefs",
   ]
 }
 
@@ -256,7 +257,6 @@
   ]
   deps = [
     ":safe_compare",
-    "..:typedefs",
     "system:inline",
   ]
 }
@@ -387,8 +387,8 @@
     ":thread_checker",
     ":timeutils",
     ":type_traits",
-    "../:typedefs",
     "system:arch",
+    "system:unused",
     "third_party/base64",
   ]
 
@@ -557,6 +557,7 @@
       ":rtc_task_queue_api",
       ":safe_conversions",
       ":timeutils",
+      "system:unused",
     ]
     if (rtc_build_libevent) {
       deps += [ "//base/third_party/libevent" ]