Add UMA histogram to count hard revokes of user certificate error decisions.

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 231196dbec0872174bc4f12ea8d1d481d8f6a10c..90bbd3997abbf6e3391626a4b6ec9ed1a4db3906 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -10309,6 +10309,16 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="interstitial.ssl.did_user_revoke_decisions"
+    enum="BooleanRevokeUserCertificateDecisions">
+  <owner>jww@chromium.org</owner>
+  <summary>
+    Specifies when a user enters the page info menu whether or not the user
+    pressed the SSL decisions revoke button. This can only by done if the user

[Alexei Svitkine (slow), 2014/08/21 19:36:11]

Please clarify when this is logged. Is it when the page info menu is closed? If
so, say so.

[jww, 2014/08/21 20:26:36]

Done.

+    is in the "Remember Certificate Error Decisions" experiment.
+  </summary>
+</histogram>
+
 <histogram name="interstitial.ssl.expiration_and_decision.nonoverridable"
     enum="SSLIsExpiredAndDecision">
   <owner>jww@chromium.org</owner>
@@ -37826,6 +37836,11 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="1" label="Reported"/>
 </enum>
 
+<enum name="BooleanRevokeUserCertificateDecisions" type="int">

[Alexei Svitkine (slow), 2014/08/21 19:36:11]

Nit: Make this just BooleanRevoked, since the enum values are not specific to
this histogram (and could be used by other histograms).

[jww, 2014/08/21 20:26:36]

Done.

+  <int value="0" label="Not revoked"/>
+  <int value="1" label="Revoked"/>
+</enum>
+
 <enum name="BooleanSelected" type="int">
   <int value="0" label="No selection"/>
   <int value="1" label="Selected"/>