[ImportantStorage] Blacklisted reason metrics

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 c93a3e4fde61ad846cfec8685dcc8094dd64d4bc..2fe3c73d1db177b2b60b7b5761d9ebabd1734bc2 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -55095,6 +55095,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Storage.BlacklistedImportantSites.Reason"
+    enum="ClearDataSiteBlacklistReason">
+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    This is recorded for every site that the user blacklists when they when they
+    clear browsing data. It tells us which signals were used to show the given

[Mark P, 2016/07/07 04:00:30]

nit: omit "us"
optional nit: tells -> indicates

+    site to the user that the user then chose to exclude from clearing.
+  </summary>
+</histogram>
+
 <histogram name="Storage.Blob.Broken" enum="BooleanBroken">
   <owner>dmurph@chromium.org</owner>
   <summary>
@@ -67914,6 +67924,17 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="613" label="X_Takri"/>
 </enum>
 
+<enum name="ClearDataSiteBlacklistReason" type="int">
+  <int value="0" label="Durable"/>
+  <int value="1" label="Notifications"/>
+  <int value="2" label="Engagement"/>
+  <int value="3" label="Notifications and Engagement"/>
+  <int value="4" label="Durable and Engagement"/>
+  <int value="5" label="Notifications and Durable"/>
+  <int value="6" label="Notifications, Durable, and Engagement"/>
+  <int value="7" label="Unknown"/>
+</enum>
+
 <enum name="ClientAppId" type="int">
   <int value="0" label="Other"/>
   <int value="1" label="Gmail"/>