[SafeBrowsing] Block dangerous unchecked downloads based on a Finch trial.

chrome/chrome_browser.gypi

Index: chrome/chrome_browser.gypi
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 13e43ad9e928c990892e935a9cfa7042f7dc6bb9..fc48cd60a2238a487b12649b709e838e598ac6f0 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -2552,6 +2552,10 @@
       'browser/safe_browsing/sandboxed_zip_analyzer.h',
       'browser/safe_browsing/two_phase_uploader.cc',
       'browser/safe_browsing/two_phase_uploader.h',
+      'browser/safe_browsing/unverified_download_field_trial.cc',
+      'browser/safe_browsing/unverified_download_field_trial.h',
+      'browser/safe_browsing/unverified_download_policy.cc',
+      'browser/safe_browsing/unverified_download_policy.h',
     ],
     'chrome_browser_search_engines_sources': [
       'browser/search_engines/chrome_template_url_service_client.cc',