Bucket FirstContentfulPaint timing into High/Low res clock buckets

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 b4f77cb3bd008baa95658385455fdfdc7b0609ab..daf7899025927988445d3040b9e16ff35b61e514 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -79260,6 +79260,12 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="Net.QuicSession.ConnectionCloseErrorCodeServer"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="HighResolutionClock" separator=".">
+  <suffix name="HighResolutionClock"
+      label="base::TimeTicks::IsHighResolution() is true for this measurement"/>
+  <affected-histogram name="PageLoad.Timing2.NavigationToFirstContentfulPaint"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="HistogramInconsistencies" separator=".">
   <suffix name="Cronet" label="Cronet histograms."/>
   <affected-histogram name="Histogram.InconsistenciesBrowser"/>
@@ -79666,6 +79672,13 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="Tabs.SadTab.KillCreated"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="LowResolutionClock" separator=".">
+  <suffix name="LowResolutionClock"

[Alexei Svitkine (slow), 2015/11/23 21:01:32]

You can list two suffix entries under the same histogram_suffixes, so please
merge them.

[Charlie Harrison, 2015/11/23 21:20:23]

Done.

+      label="base::TimeTicks::IsHighResolution() is false for this
+             measurement"/>
+  <affected-histogram name="PageLoad.Timing2.NavigationToFirstContentfulPaint"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="ManifestProperties" separator=".">
   <suffix name="name"/>
   <suffix name="short_name"/>