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 1acbda2d6e33be35c5a03d484d8b6856df2e0261..bf6c72950c2139b4a82e1226737f618b1430eaf9 100644
--- a/webrtc/modules/desktop_capture/screen_capturer_mac.mm
+++ b/webrtc/modules/desktop_capture/screen_capturer_mac.mm
@@ -25,6 +25,7 @@
 #include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.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"
@@ -36,7 +37,6 @@
 #include "webrtc/modules/desktop_capture/screen_capturer_helper.h"
 #include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
 #include "webrtc/system_wrappers/include/logging.h"
-#include "webrtc/system_wrappers/include/tick_util.h"
 
 namespace webrtc {
 
@@ -384,7 +384,7 @@ 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();
   RTC_DCHECK(!queue_.current_frame() || !queue_.current_frame()->IsShared());
@@ -448,7 +448,8 @@ 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);
 }