Replace DCHECK() upon unexpected x11 event time with a workaround

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 117c618a518207c98f3c2111644260c912f7c9d4..9fa065a3e114f65ab7621d7ef32e0eea8c80ebf9 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -12410,6 +12410,17 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Event.TimestampHasValidTimebase" enum="EventTimestampValidity">
+  <owner>majidvp@chromium.org</owner>
+  <owner>tdresser@chromium.org</owner>
+  <owner>caseq@chromium.org</owner>
+  <summary>
+    Whether the timestapms on input events produced by the windowing system
+    appear to be sharing the same time base as TimeTicks, modulo possible
+    roll-over.
+  </summary>
+</histogram>
+
 <histogram name="Event.Touch.TargetAndDispatchResult"
     enum="TouchTargetAndDispatchResultType">
   <obsolete>
@@ -69735,6 +69746,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="5" label="Forced Non-Blocking"/>
 </enum>
 
+<enum name="EventTimestampValidity" type="int">
+  <int value="0" label="Invalid time base"/>
+  <int value="1" label="Valid time base"/>
+</enum>
+
 <enum name="EVWhitelistStatus" type="int">
   <int value="0" label="Not present"/>
   <int value="1" label="Invalid"/>