Add a new ThreatSource type to indicate SBHit is from client side detection.

chrome/browser/safe_browsing/safe_browsing_blocking_page.cc

Index: chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
index 48b534e2ef23f5518949cf5c9abcf37cc8123dc3..5c71fa63c1b0422b5f2f9b0668be5e303841e1d6 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
@@ -555,6 +555,8 @@ std::string SafeBrowsingBlockingPage::GetExtraMetricsSuffix() const {
       return "from_device";
     case safe_browsing::ThreatSource::LOCAL_PVER4:
       return "from_device_v4";
+    case safe_browsing::ThreatSource::CLIENT_SIDE_DETECTION:
+      return "from_client_side_detection";
     case safe_browsing::ThreatSource::UNKNOWN:
       break;
   }