Revert "Adding UMA to track previews opt outs and blacklist eligibility"

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 937917f6d9ab1c92083a7f6f440dfe263eaff239..568fa929ed5d74e3f9a3a14378bfa1e6cea5a9f7 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -48340,15 +48340,6 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
-<histogram name="Previews.EligibilityReason.Offline"
-    enum="PreviewsEligibilityReason">
-  <owner>ryansturm@chromium.org</owner>
-  <summary>
-    Whether an offline preview was allowed to be shown or the reason the preview
-    could not be shown to the user.
-  </summary>
-</histogram>
-
 <histogram name="Previews.InfoBarAction.LitePage" enum="PreviewsInfoBarAction">
   <owner>bengr@chromium.org</owner>
   <owner>megjablon@chromium.org</owner>
@@ -48395,15 +48386,6 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
-<histogram name="Previews.OptOut.UserOptedOut.Offline"
-    enum="PreviewsUserOptedOut">
-  <owner>ryansturm@chromium.org</owner>
-  <summary>
-    Whether the user chose to reload the full page when shown an offline
-    preview.
-  </summary>
-</histogram>
-
 <histogram name="Previews.OriginalContentLength" units="KB">
   <owner>ryansturm@chromium.org</owner>
   <summary>
@@ -96656,17 +96638,6 @@ value.
   <int value="4" label="'Load images' context menu item clicked"/>
 </enum>
 
-<enum name="PreviewsEligibilityReason" type="int">
-  <int value="0" label="Preview Allowed."/>
-  <int value="1" label="Blacklist not created."/>
-  <int value="2" label="Blacklist data not loaded yet from disk."/>
-  <int value="3" label="User opted out of a preview recently."/>
-  <int value="4" label="User is blacklisted for all hosts."/>
-  <int value="5" label="User is blacklisted for the specific host."/>
-  <int value="6" label="The network quality estimate is not available."/>
-  <int value="7" label="The network is not slow enough to show previews."/>
-</enum>
-
 <enum name="PreviewsInfoBarAction" type="int">
   <int value="0" label="Infobar shown"/>
   <int value="1" label="Infobar 'Load original' clicked"/>
@@ -96674,11 +96645,6 @@ value.
   <int value="3" label="Infobar dismissed by navigation"/>
 </enum>
 
-<enum name="PreviewsUserOptedOut" type="int">
-  <int value="0" label="The user did not choose to reload the full page."/>
-  <int value="1" label="The user chose to reload the full page."/>
-</enum>
-
 <enum name="PrinterServiceEventType" type="int">
   <int value="0" label="Printer added"/>
   <int value="1" label="Page displayed (Deprecated)"/>