MD Settings: Add feature flag for showing content settings in a per-origin view.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 6b4eb075fd465f7cc3d3c8c908874982f32810d9..16a1c175d5ab297e2421e5a434120713c5e41c0d 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1210,6 +1210,9 @@ const FeatureEntry kFeatureEntries[] = {
     {"top-chrome-md", flag_descriptions::kTopChromeMd,
      flag_descriptions::kTopChromeMdDescription, kOsDesktop,
      MULTI_VALUE_TYPE(kTopChromeMaterialDesignChoices)},
+    {"enable-site-details", flag_descriptions::kSiteDetails,
+     flag_descriptions::kSiteDetailsDescription, kOsDesktop,
+     FEATURE_VALUE_TYPE(features::kSiteDetails)},
     {"enable-site-settings", flag_descriptions::kSiteSettings,
      flag_descriptions::kSiteSettingsDescription, kOsDesktop,
      SINGLE_VALUE_TYPE(switches::kEnableSiteSettings)},