Add metrics for Safe Browsing blacklist response.

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 7e6c9d5b4ef8a565ba5c0584502e936afe70af9e..e2fc5752189aac40ac15d9eb49b81ecc8edc09ea 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -46045,6 +46045,28 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Permissions.AutoBlocker.SafeBrowsingResponse"
+    enum="SafeBrowsingResponse">
+  <owner>dominickn@chromium.org</owner>
+  <owner>kcarattini@chromium.org</owner>
+  <summary>
+    Tracks the response (if received) from Safe Browsing when the API blacklist
+    is queried for an (origin, permission) pair. The response could be that the
+    origin was blacklisted, not blacklisted, or Safe Browsing timed out before a
+    response was received.
+  </summary>
+</histogram>
+
+<histogram name="Permissions.AutoBlocker.SafeBrowsingResponseTime" units="ms">
+  <owner>dominickn@chromium.org</owner>
+  <owner>kcarattini@chromium.org</owner>
+  <summary>
+    Records the elapsed time between the client sending a request to Safe
+    Browsing and receiving a result, or the maximum wait time is exceeded and
+    Safe Browsing is deemed to have timed out.
+  </summary>
+</histogram>
+
 <histogram name="Permissions.Prompt.Accepted" enum="PermissionRequestType">
   <owner>dominickn@chromium.org</owner>
   <owner>kcarattini@chromium.org</owner>
@@ -104942,6 +104964,12 @@ value.
   <int value="4" label="NO_STATE_ERROR"/>
 </enum>
 
+<enum name="SafeBrowsingResponse" type="int">
+  <int value="0" label="NOT_BLACKLISTED"/>
+  <int value="1" label="TIMEOUT"/>
+  <int value="2" label="BLACKLISTED"/>
+</enum>
+
 <enum name="SafeBrowsingV4ApplyUpdateResult" type="int">
   <int value="0" label="APPLY_UPDATE_SUCCESS"/>
   <int value="1" label="UNEXPECTED_APPLY_UPDATE_FAILURE"/>