Change default timestamp to 64 bits in all webrtc directories.

webrtc/pc/currentspeakermonitor.cc

Index: webrtc/pc/currentspeakermonitor.cc
diff --git a/webrtc/pc/currentspeakermonitor.cc b/webrtc/pc/currentspeakermonitor.cc
index bbb33e3143c6cc21eab60ded40e4ea35fdbc276b..4871a6883881bb8f3f110bbbef9f0b50f4511bde 100644
--- a/webrtc/pc/currentspeakermonitor.cc
+++ b/webrtc/pc/currentspeakermonitor.cc
@@ -61,7 +61,7 @@ void CurrentSpeakerMonitor::Stop() {
 }
 
 void CurrentSpeakerMonitor::set_min_time_between_switches(
-    uint32_t min_time_between_switches) {
+    int min_time_between_switches) {
   min_time_between_switches_ = min_time_between_switches;
 }
 
@@ -163,7 +163,7 @@ void CurrentSpeakerMonitor::OnAudioMonitor(
 
   // We avoid over-switching by disabling switching for a period of time after
   // a switch is done.
-  uint32_t now = rtc::Time();
+  int64_t now = rtc::Time();
   if (earliest_permitted_switch_time_ <= now &&
       current_speaker_ssrc_ != loudest_speaker_ssrc) {
     current_speaker_ssrc_ = loudest_speaker_ssrc;