Metrics for tracking Safe Browsing hit patterns for the Safe Browsing lists Subresource Filter.

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 9bc93150da2a4b1e2722d224bde95790dda6ec31..3d4214ede0dc8c912f743132934ed0bc6de04d40 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -63070,6 +63070,24 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="SubresourceFilter.PageLoad.RedirectChainLength" units="urls">
+  <owner>melandory@chromium.org</owner>
+  <summary>Total length of the server redirects during the navigation.</summary>
+</histogram>
+
+<histogram name="SubresourceFilter.PageLoad.RedirectChainMatchPattern"
+    enum="SubresourceFilterMatchPattern">
+  <owner>melandory@chromium.org</owner>
+  <summary>
+    For each main frame navigation, records a pattern that indicates which URLs
+    in the redirect chain matched Safe Browsing blacklists, and which did not.
+    For example, for the redirect chain A-B-C-D metric tracks: 1. If initial URL
+    (A) was on a Safe Browsing blacklist. 2. If any if middle urls (B, C) were
+    on a Safe Browsing blacklist. 3. If committed URL (B) was on a Safe Browsing
+    blacklist.
+  </summary>
+</histogram>
+
 <histogram name="SubresourceFilter.Prompt.NumReloads" enum="BooleanRequested">
   <owner>melandory@chromium.org</owner>
   <summary>
@@ -102168,6 +102186,18 @@ value.
   <int value="2" label="Enabled"/>
 </enum>
 
+<enum name="SubresourceFilterMatchPattern" type="int">
+  <int value="0" label="NoHit"/>
+  <int value="1" label="Last"/>
+  <int value="2" label="Middle"/>
+  <int value="3" label="Middle_Last"/>
+  <int value="4" label="First"/>
+  <int value="5" label="First_Last"/>
+  <int value="6" label="First_Middle"/>
+  <int value="7" label="AllHits"/>
+  <int value="8" label="NoRedirectsHit"/>
+</enum>
+
 <enum name="SubresourceFilterWriteRulesetResult" type="int">
   <int value="0" label="Success"/>
   <int value="1" label="FailedCreatingScratchDir"/>