Make the OutdatedBuildDetector feature static.

chrome/browser/upgrade_detector_impl.cc

Index: chrome/browser/upgrade_detector_impl.cc
diff --git a/chrome/browser/upgrade_detector_impl.cc b/chrome/browser/upgrade_detector_impl.cc
index 2f628ddfa48ffe2d1ee6a512cbc13a5d15505757..063ac0bac778ab466910549d4cc413f94d6317f7 100644
--- a/chrome/browser/upgrade_detector_impl.cc
+++ b/chrome/browser/upgrade_detector_impl.cc
@@ -378,8 +378,8 @@ void UpgradeDetectorImpl::CheckForUpgrade() {
 }
 
 bool UpgradeDetectorImpl::DetectOutdatedInstall() {
-  constexpr base::Feature kOutdatedBuildDetector =
-      { "OutdatedBuildDetector", base::FEATURE_ENABLED_BY_DEFAULT };
+  static constexpr base::Feature kOutdatedBuildDetector = {
+      "OutdatedBuildDetector", base::FEATURE_ENABLED_BY_DEFAULT};
 
   if (!base::FeatureList::IsEnabled(kOutdatedBuildDetector))
     return false;