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

webrtc/api/statscollector.cc

Index: webrtc/api/statscollector.cc
diff --git a/webrtc/api/statscollector.cc b/webrtc/api/statscollector.cc
index ffe241568bd4a141f17e0071276e1cbe6920f411..e85a9eb69a547af9aa450335caad726b8146dab3 100644
--- a/webrtc/api/statscollector.cc
+++ b/webrtc/api/statscollector.cc
@@ -17,7 +17,6 @@
 #include "webrtc/api/peerconnection.h"
 #include "webrtc/base/base64.h"
 #include "webrtc/base/checks.h"
-#include "webrtc/base/timing.h"
 #include "webrtc/pc/channel.h"
 
 namespace webrtc {
@@ -376,7 +375,7 @@ StatsCollector::~StatsCollector() {
 }
 
 double StatsCollector::GetTimeNow() {
-  return rtc::Timing::WallTimeNow() * rtc::kNumMillisecsPerSec;
+  return rtc::WallClockSeconds();
 }
 
 // Adds a MediaStream with tracks that can be used as a |selector| in a call