Support --delete-old-versions in setup.exe.

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 572df64892ceaba364058b3d2e89d21df86ea4a6..916d613b371cb15925ad18111f903b734fa6b6d9 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -55478,6 +55478,33 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram
+    name="Setup.Install.NumDeleteOldVersionsAttemptsBeforeSingletonReleased"
+    units="Attempts">
+  <owner>fdoray@chromium.org</owner>
+  <summary>
+    Number of unsuccessful calls to DeleteOldVerions() made by a
+    --delete-old-versions process before it had to release the SetupSingleton. A
+    --delete-old-versions process that successfully acquires the SetupSingleton
+    records to either the
+    Setup.Install.NumDeleteOldVersionsAttemptsBeforeSingletonReleased histogram
+    or the Setup.Install.NumDeleteOldVersionsAttemptsBeforeSuccess histogram.
+  </summary>
+</histogram>
+
+<histogram name="Setup.Install.NumDeleteOldVersionsAttemptsBeforeSuccess"
+    units="Attempts">
+  <owner>fdoray@chromium.org</owner>
+  <summary>
+    Number of calls to DeleteOldVersions() made by a --delete-old-versions
+    process that successfully deleted all files that belong to old versions of
+    Chrome. A --delete-old-versions process that successfully acquires the
+    SetupSingleton records to either the
+    Setup.Install.NumDeleteOldVersionsAttemptsBeforeSingletonReleased histogram
+    or the Setup.Install.NumDeleteOldVersionsAttemptsBeforeSuccess histogram.
+  </summary>
+</histogram>
+
 <histogram name="Setup.Install.PeakPagefileUsage" units="KB">
   <owner>huangs@chromium.org</owner>
   <summary>
@@ -84380,6 +84407,8 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="58" label="IN_USE_DOWNGRADE"/>
   <int value="59" label="OLD_VERSION_DOWNGRADE"/>
   <int value="60" label="SETUP_SINGLETON_ACQUISITION_FAILED"/>
+  <int value="61" label="SETUP_SINGLETON_RELEASED"/>
+  <int value="62" label="DELETE_OLD_VERSIONS_SUCCESS"/>
 </enum>
 
 <enum name="InstantControllerEvent" type="int">