Delete Timing class, timing.h, and update all users.

webrtc/stats/rtcstatscollector.cc

Index: webrtc/stats/rtcstatscollector.cc
diff --git a/webrtc/stats/rtcstatscollector.cc b/webrtc/stats/rtcstatscollector.cc
index 4bedad62eea674333b2ffbc178ed7b60a9a8b36c..0acb30484b75ed07df3e32daf6aac630d641af67 100644
--- a/webrtc/stats/rtcstatscollector.cc
+++ b/webrtc/stats/rtcstatscollector.cc
@@ -16,7 +16,6 @@
 
 #include "webrtc/api/peerconnection.h"
 #include "webrtc/base/checks.h"
-#include "webrtc/base/timing.h"
 
 namespace webrtc {
 
@@ -43,8 +42,7 @@ rtc::scoped_refptr<const RTCStatsReport> RTCStatsCollector::GetStatsReport() {
   // "Now" using a system clock, relative to the UNIX epoch (Jan 1, 1970, UTC),
   // in microseconds. The system clock could be modified and is not necessarily
   // monotonically increasing.
-  int64_t timestamp_us = static_cast<int64_t>(
-      rtc::Timing::WallTimeNow() * rtc::kNumMicrosecsPerSec);
+  int64_t timestamp_us = rtc::TimeUTCMicros();
 
   rtc::scoped_refptr<RTCStatsReport> report = RTCStatsReport::Create();
   report->AddStats(ProducePeerConnectionStats(timestamp_us));