Change default timestamp to 64 bits in all webrtc directories.

webrtc/video/end_to_end_tests.cc

Index: webrtc/video/end_to_end_tests.cc
diff --git a/webrtc/video/end_to_end_tests.cc b/webrtc/video/end_to_end_tests.cc
index 9094b13003472dbedfefdeb1ee4b88f168ce6ea3..10b85b942b7861f0fe15457f6f9f1002d07dd0a1 100644
--- a/webrtc/video/end_to_end_tests.cc
+++ b/webrtc/video/end_to_end_tests.cc
@@ -2930,7 +2930,7 @@ void EndToEndTest::TestRtpStatePreservation(bool use_rtx) {
       } else {
         // Verify timestamps are reasonably close.
         uint32_t latest_observed = timestamp_it->second;
-        int32_t timestamp_gap = rtc::TimeDiff(timestamp, latest_observed);
+        int32_t timestamp_gap = rtc::TimeDiff32(timestamp, latest_observed);
         EXPECT_LE(std::abs(timestamp_gap), kMaxTimestampGap)
             << "Gap in timestamps (" << latest_observed << " -> "
             << timestamp << ") too large for SSRC: " << ssrc << ".";