Move ThreadWrapper to ProcessThread in base.

webrtc/system_wrappers/BUILD.gn

Index: webrtc/system_wrappers/BUILD.gn
diff --git a/webrtc/system_wrappers/BUILD.gn b/webrtc/system_wrappers/BUILD.gn
index d0447e9ca1b51b04558c67cdee14a2d1b764a8f5..5e0e41e832265075bfe3527aa2eab0e2f63fa84e 100644
--- a/webrtc/system_wrappers/BUILD.gn
+++ b/webrtc/system_wrappers/BUILD.gn
@@ -37,7 +37,6 @@ static_library("system_wrappers") {
     "include/static_instance.h",
     "include/stl_util.h",
     "include/stringize_macros.h",
-    "include/thread_wrapper.h",
     "include/tick_util.h",
     "include/timestamp_extrapolator.h",
     "include/trace.h",
@@ -79,11 +78,6 @@ static_library("system_wrappers") {
     "source/rw_lock_win.h",
     "source/sleep.cc",
     "source/sort.cc",
-    "source/thread.cc",
-    "source/thread_posix.cc",
-    "source/thread_posix.h",
-    "source/thread_win.cc",
-    "source/thread_win.h",
     "source/tick_util.cc",
     "source/timestamp_extrapolator.cc",
     "source/trace_impl.cc",
@@ -193,9 +187,9 @@ source_set("system_wrappers_default") {
   public_configs = [ "..:common_inherited_config" ]
 
   deps = [
-    ":system_wrappers",
     ":field_trial_default",
     ":metrics_default",
+    ":system_wrappers",
   ]
 }