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 1dd9c545a78f4e7af695a67016fff27854fd05c0..46e4d40e6be2600103032a06974cb47bafc2c6b2 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -33936,6 +33936,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="OfflinePages.ArchiveDirCreationTime">
+  <owner>dewittj@chromium.org</owner>
+  <owner>jianli@chromium.org</owner>
+  <summary>
+    The amount of time to create the offline pages archive directory.
+  </summary>
+</histogram>

[Pete Williamson, 2016/05/06 16:57:14]

Why would we measure the directory creation time?  It seems like something that
only happens once per user (unless they clear the cache), and should be
relatively short.

Also, I don't see any calls to collect this UMA.

[dewittj, 2016/05/06 18:26:02]

I expect that indeed it is, however I don't know for sure.  So I thought I'd
measure it.  What if /all/ FS operations are super slow for crappy phones?
line 579 of offline_page_model.cc

+
 <histogram name="OfflinePages.BatchDelete.Count">
   <owner>jianli@chromium.org</owner>
   <summary>Number of offline pages that are deleted in a batch.</summary>
@@ -34093,6 +34101,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="OfflinePages.ModelLoadTime">
+  <owner>dewittj@chromium.org</owner>
+  <owner>jianli@chromium.org</owner>
+  <summary>
+    The amount of time to create the offline pages archive directory and load
+    the offline page model.
+  </summary>
+</histogram>
+
 <histogram name="OfflinePages.OfflinePageCount">
   <owner>fgorski@chromium.org</owner>
   <owner>jianli@chromium.org</owner>