Avoid timestamp update when data is kept on dump

Bug: 158703584
Test: atest statsd_test
Change-Id: Ia6814c2cdb67dde2fd790ddc18fc785b1bba062c
diff --git a/cmds/statsd/src/metrics/MetricsManager.cpp b/cmds/statsd/src/metrics/MetricsManager.cpp
index e8c575a..7e825ef 100644
--- a/cmds/statsd/src/metrics/MetricsManager.cpp
+++ b/cmds/statsd/src/metrics/MetricsManager.cpp
@@ -361,8 +361,12 @@
         protoOutput->end(token);
     }
 
-    mLastReportTimeNs = dumpTimeStampNs;
-    mLastReportWallClockNs = getWallClockNs();
+    // Do not update the timestamps when data is not cleared to avoid timestamps from being
+    // misaligned.
+    if (erase_data) {
+        mLastReportTimeNs = dumpTimeStampNs;
+        mLastReportWallClockNs = getWallClockNs();
+    }
     VLOG("=========================Metric Reports End==========================");
 }