Delete all use of tick_util.h.

webrtc/modules/desktop_capture/screen_capturer_mac.mm

Index: webrtc/modules/desktop_capture/screen_capturer_mac.mm
diff --git a/webrtc/modules/desktop_capture/screen_capturer_mac.mm b/webrtc/modules/desktop_capture/screen_capturer_mac.mm
index c41dc4d7a3b4ba59e4ebe6880f1e090dae5386b5..39bfed127f43c18e2ef7d67e43ae43883c1d6c6c 100644
--- a/webrtc/modules/desktop_capture/screen_capturer_mac.mm
+++ b/webrtc/modules/desktop_capture/screen_capturer_mac.mm
@@ -23,6 +23,7 @@
 #include <OpenGL/OpenGL.h>
 
 #include "webrtc/base/macutils.h"
+#include "webrtc/base/timeutils.h"
 #include "webrtc/modules/desktop_capture/desktop_capture_options.h"
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
 #include "webrtc/modules/desktop_capture/desktop_geometry.h"
@@ -33,7 +34,6 @@
 #include "webrtc/modules/desktop_capture/screen_capture_frame_queue.h"
 #include "webrtc/modules/desktop_capture/screen_capturer_helper.h"
 #include "webrtc/system_wrappers/include/logging.h"
-#include "webrtc/system_wrappers/include/tick_util.h"
 
 namespace webrtc {
 
@@ -381,7 +381,7 @@ void ScreenCapturerMac::Start(Callback* callback) {
 }
 
 void ScreenCapturerMac::Capture(const DesktopRegion& region_to_capture) {
-  TickTime capture_start_time = TickTime::Now();
+  int64_t capture_start_time_nanos = rtc::TimeNanos();
 
   queue_.MoveToNextFrame();
 
@@ -444,7 +444,8 @@ void ScreenCapturerMac::Capture(const DesktopRegion& region_to_capture) {
   desktop_config_monitor_->Unlock();
 
   new_frame->set_capture_time_ms(
-      (TickTime::Now() - capture_start_time).Milliseconds());
+      (rtc::TimeNanos() - capture_start_time_nanos) /
+      rtc::kNumNanosecsPerMillisec);
   callback_->OnCaptureCompleted(new_frame);
 }