[SafeBrowsing] Conditionalize unverified download blocking on whitelist.

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 7081e03d8b924d326cc15afbdec95e2333a2e8f4..ee0b465575d9924bb06d96be89de1ec2d8bd8ac0 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -38485,6 +38485,28 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="SafeBrowsing.UnverifiedDownloads.AllowedByWhitelist"
+    enum="SBClientDownloadExtensions">
+  <owner>asanka@chromium.org</owner>
+  <summary>
+    File types that were allowed to be downloaded without verifying their
+    content nor their source URLs with Safe Browsing due to the requestor URL
+    being on the Safe Browsing whitelist. Each sample recorded on this histogram
+    is also recorded in SafeBrowsing.UnverifiedDownloads.Allowed.
+  </summary>
+</histogram>
+
+<histogram name="SafeBrowsing.UnverifiedDownloads.AllowedDueToDisabledService"
+    enum="SBClientDownloadExtensions">
+  <owner>asanka@chromium.org</owner>
+  <summary>
+    File types that were allowed to be downloaded without verifying their
+    content nor their source URLs with Safe Browsing due to the SafeBrowsing
+    service being disabled. Each sample recorded on this histogram is also
+    recorded in SafeBrowsing.UnverifiedDownloads.Allowed.
+  </summary>
+</histogram>
+
 <histogram name="SafeBrowsing.UnverifiedDownloads.Blocked"
     enum="SBClientDownloadExtensions">
   <owner>asanka@chromium.org</owner>