Implement important sites dialog for desktop.

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 0a423b8073aac3df7baf89bb5f4404bdd16a06d5..6fb8110e8284c5d64d7ef89e4e1cd5cbb014ed7e 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -2334,10 +2334,10 @@ const FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kFullscreenToolbarRevealDescription, kOsMac,
      SINGLE_VALUE_TYPE(switches::kEnableFullscreenToolbarReveal)},
 #endif  // OS_MACOSX
-#if defined(OS_ANDROID)
     {"important-sites-in-cbd", flag_descriptions::kImportantSitesInCbdName,
-     flag_descriptions::kImportantSitesInCbdDescription, kOsAndroid,
-     FEATURE_VALUE_TYPE(chrome::android::kImportantSitesInCBD)},
+     flag_descriptions::kImportantSitesInCbdDescription, kOsAll,
+     FEATURE_VALUE_TYPE(features::kImportantSitesInCbd)},
+#if defined(OS_ANDROID)
     {"tabs-in-cbd", flag_descriptions::kTabsInCbdName,
      flag_descriptions::kTabsInCbdDescription, kOsAndroid,
      FEATURE_VALUE_TYPE(features::kTabsInCbd)},