Change default timestamp to 64 bits in all webrtc directories.

webrtc/api/dtmfsender_unittest.cc

Index: webrtc/api/dtmfsender_unittest.cc
diff --git a/webrtc/api/dtmfsender_unittest.cc b/webrtc/api/dtmfsender_unittest.cc
index efe568da842c0cb18d9580911541fdd31018ba10..e5fe26171b504701692fe6296930caa5a77acead 100644
--- a/webrtc/api/dtmfsender_unittest.cc
+++ b/webrtc/api/dtmfsender_unittest.cc
@@ -85,9 +85,9 @@ class FakeDtmfProvider : public DtmfProviderInterface {
     // TODO(ronghuawu): Make the timer (basically the rtc::TimeNanos)
     // mockable and use a fake timer in the unit tests.
     if (last_insert_dtmf_call_ > 0) {
-      gap = static_cast<int>(rtc::Time() - last_insert_dtmf_call_);
+      gap = static_cast<int>(rtc::TimeMillis() - last_insert_dtmf_call_);
     }
-    last_insert_dtmf_call_ = rtc::Time();
+    last_insert_dtmf_call_ = rtc::TimeMillis();
 
     LOG(LS_VERBOSE) << "FakeDtmfProvider::InsertDtmf code=" << code
                     << " duration=" << duration