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/base/logging.cc b/webrtc/base/logging.cc
index 6265668..6060362 100644
--- a/webrtc/base/logging.cc
+++ b/webrtc/base/logging.cc
@@ -124,7 +124,7 @@
                        const char* module)
     : severity_(sev), tag_(kLibjingle) {
   if (timestamp_) {
-    uint32_t time = TimeSince(LogStartTime());
+    int64_t time = TimeSince(LogStartTime());
     // Also ensure WallClockStartTime is initialized, so that it matches
     // LogStartTime.
     WallClockStartTime();
@@ -209,8 +209,8 @@
   }
 }
 
-uint32_t LogMessage::LogStartTime() {
-  static const uint32_t g_start = Time();
+int64_t LogMessage::LogStartTime() {
+  static const int64_t g_start = TimeMillis();
   return g_start;
 }