LeveldbValueStore: Deleting db when open fails due to corruption.

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 366a3f741f8d825ed293d17d3f003fe64f9acdb2..dfc59c4bcb45d548851369aee0fb1f865f80f36e 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -11362,6 +11362,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>The result of an open attempt to an Extensions database.</summary>
 </histogram>
 
+<histogram name="Extensions.Database.Restore"
+    enum="LevelDBCorruptionRestoreValue">
+  <owner>cmumford@chromium.org</owner>
+  <summary>
+    The result of an attempt to recover from an attempt to open a database that
+    failed as a result of corruption.
+  </summary>
+</histogram>
+
 <histogram name="Extensions.DeclarativeRulesStorageInitialization"
     units="milliseconds">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
@@ -64955,6 +64964,12 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="4" label="Bookmark shortcut widget"/>
 </enum>
 
+<enum name="LevelDBCorruptionRestoreValue" type="int">
+  <int value="0" label="Delete Success"/>
+  <int value="1" label="Delete Failure"/>
+  <int value="2" label="Repair Success"/>

[Devlin, 2015/11/06 19:54:46]

Missing one, right?

[rkaplow, 2015/11/06 23:06:51]

this is all that is tracked, actually.

[cmumford, 2015/11/09 23:04:22]

These correlate to the vales in LevelDBCorruptionRecoveryValue (from
leveldb_value_store.cc).

+</enum>
+
 <enum name="LevelDBCorruptionTypes" type="int">
   <int value="0" label="other"/>
   <int value="1" label="missing files"/>
@@ -77482,6 +77497,13 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="Extensions.Database.Open"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="ExtensionsDatabaseRestore" separator=".">
+  <suffix name="Rules" label="Rules backing stores"/>
+  <suffix name="Settings" label="Settings backing stores"/>
+  <suffix name="State" label="State backing stores"/>
+  <affected-histogram name="Extensions.Database.Restore"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="ExternalExtensionEvent" separator="">
   <suffix name="NonWebstore"
       label="sideloaded extensions that don't update from the webstore"/>