Change default timestamp to 64 bits in all webrtc directories.

BUG=
R=pbos@webrtc.org, pthatcher@webrtc.org, solenberg@webrtc.org

Review URL: https://codereview.webrtc.org/1835053002 .

Cr-Commit-Position: refs/heads/master@{#12646}
diff --git a/webrtc/api/peerconnectionfactory.cc b/webrtc/api/peerconnectionfactory.cc
index ff8098c..b2a3798 100644
--- a/webrtc/api/peerconnectionfactory.cc
+++ b/webrtc/api/peerconnectionfactory.cc
@@ -153,7 +153,7 @@
 
 bool PeerConnectionFactory::Initialize() {
   RTC_DCHECK(signaling_thread_->IsCurrent());
-  rtc::InitRandom(rtc::Time());
+  rtc::InitRandom(rtc::Time32());
 
   default_network_manager_.reset(new rtc::BasicNetworkManager());
   if (!default_network_manager_) {