Histogram versions and extended error codes for SQLite databases.

tools/metrics/histograms/histograms.xml

 <!--
 Copyright 2013 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
 <!--
 This file is used to generate a comprehensive list of Chrome histograms along
 with a detailed description for each histogram.
 
@@ skipping 6745 matching lines @@
 </histogram>
 
 <histogram name="SimpleCache.SyncOpenResult" enum="SimpleCacheSyncOpenResult">
   <summary>The result of attempting to create a new cache entry.</summary>
 </histogram>
 
 <histogram name="Sqlite.AppCache.Error" enum="SqliteErrorCode">
   <summary>Error codes returned by sqlite for the appcache db.</summary>
 </histogram>
 
+<histogram name="Sqlite.AppCache.Version">
+  <summary>Appcache db version at startup.</summary>

[jar (doing other things), 2013/05/07 23:46:41]

For each of these histograms.... can you give me a sense of how many distinct
buckets we'd expect to see across our fleet of Chrome users?  Are these things
like "about 3-5 versions a year" or "each day a new version is invented??"

+</histogram>
+
 <histogram name="Sqlite.Cookie.Error" enum="SqliteErrorCode">
-  <summary>Error codes returned by sqlite the cookie db.</summary>
+  <summary>Error codes returned by sqlite for the cookie db.</summary>
+</histogram>
+
+<histogram name="Sqlite.Cookie.Version">
+  <summary>Cookie db version at startup.</summary>
 </histogram>
 
 <histogram name="Sqlite.DatabaseTracker.Error" enum="SqliteErrorCode">
-  <summary>Error codes returned by sqlite the websqldb tracker db.</summary>
+  <summary>Error codes returned by sqlite for the websqldb tracker db.</summary>
+</histogram>
+
+<histogram name="Sqlite.DatabaseTracker.Version">
+  <summary>Websqldb tracker db version at startup.</summary>
 </histogram>
 
 <histogram name="Sqlite.DomainBoundCerts.Error" enum="SqliteErrorCode">
   <summary>
     Error codes returned by sqlite for the domain-bound certs db.
   </summary>
 </histogram>
 
+<histogram name="Sqlite.DomainBoundCerts.Version">
+  <summary>Domain-bound certs db version at startup.</summary>
+</histogram>
+
 <histogram name="Sqlite.DomStorageDatabase.Error" enum="SqliteErrorCode">
   <summary>Error codes returned by sqlite for the domstorage db.</summary>
 </histogram>
 
+<histogram name="Sqlite.DomStorageDatabase.Version">
+  <summary>Domstorage db version at startup.</summary>
+</histogram>
+
 <histogram name="Sqlite.Error" enum="SqliteErrorCode">
   <summary>Error codes returned by sqlite for all databases.</summary>
 </histogram>
 
 <histogram name="Sqlite.Error.IOERR" enum="SqliteIOERRCode">
-  <summary>Error codes returned by sqlite for all databases.</summary>
+  <summary>
+    Extended SQLITE_IOERR codes returned by sqlite for all databases.
+  </summary>
 </histogram>
 
 <histogram name="Sqlite.History.Error" enum="SqliteErrorCode">
   <summary>Error codes returned by sqlite for the history db.</summary>
 </histogram>
 
+<histogram name="Sqlite.History.Version">
+  <summary>History db version at startup.</summary>
+</histogram>
+
 <histogram name="Sqlite.Quota.Error" enum="SqliteErrorCode">
   <summary>Error codes returned by sqlite for the quota db.</summary>
 </histogram>
 
+<histogram name="Sqlite.Quota.Version">
+  <summary>Quota db version at startup.</summary>
+</histogram>
+
 <histogram name="Sqlite.Text.Error" enum="SqliteErrorCode">
-  <summary>Error codes returned by sqlite the full text db.</summary>
+  <summary>Error codes returned by sqlite for the full text db.</summary>
+</histogram>
+
+<histogram name="Sqlite.Text.Version">
+  <summary>Full-text db version at startup.</summary>
 </histogram>
 
 <histogram name="Sqlite.Thumbnail.Error" enum="SqliteErrorCode">
   <summary>Error codes returned by sqlite for the thumbnail db.</summary>
 </histogram>
 
+<histogram name="Sqlite.Thumbnail.Version">
+  <summary>Thumbnail db version at startup.</summary>
+</histogram>
+
+<histogram name="Sqlite.TopSites.Error" enum="SqliteErrorCode">
+  <summary>Error codes returned by sqlite for the top sites db.</summary>
+</histogram>
+
+<histogram name="Sqlite.TopSites.Version">
+  <summary>Top sites db version at startup.</summary>
+</histogram>
+
 <histogram name="Sqlite.Web.Error" enum="SqliteErrorCode">
-  <summary>Error codes returned by sqlite the web db.</summary>
+  <summary>Error codes returned by sqlite for the web db.</summary>
+</histogram>
+
+<histogram name="Sqlite.Web.Version">
+  <summary>Web db version at startup.</summary>
 </histogram>
 
 <histogram name="Tab.SwitchedToForegroundAge" units="ms">
   <summary>Age (in ms) when the tab was switched to foreground.</summary>
 </histogram>
 
 <histogram name="Tab.SwitchedToForegroundLaunchedWithURL"
     enum="TabSwitchedToForegroundLaunchedWithURL">
   <summary>
     Each time a tab is brought to the foreground, this histogram indicates if
@@ skipping 5163 matching lines @@
 <fieldtrial name="SSLResumption">
   <group name="Resume_Handshake" label="Session Resumption"/>
   <group name="Full_Handshake" label="Full"/>
   <affected-histogram name="Net.SSL_Connection_Latency"/>
   <affected-histogram name="Net.SSL_Connection_Latency_Google"/>
 </fieldtrial>
 
 </fieldtrials>
 
 </histogram-configuration>