In-app messaging to communicate the imminent 32-bit deprecation to 32-bit-only users

chrome/browser/ui/webui/help/version_updater_mac.mm

Index: chrome/browser/ui/webui/help/version_updater_mac.mm
diff --git a/chrome/browser/ui/webui/help/version_updater_mac.mm b/chrome/browser/ui/webui/help/version_updater_mac.mm
index 130f6768a52c665668c9cad87f02e5c373734fc7..56586d36d7a2a9627008aac2579ed67afe6abf9c 100644
--- a/chrome/browser/ui/webui/help/version_updater_mac.mm
+++ b/chrome/browser/ui/webui/help/version_updater_mac.mm
@@ -8,6 +8,7 @@
 #include "base/bind_helpers.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #import "chrome/browser/mac/keystone_glue.h"
+#include "chrome/browser/mac/obsolete_system.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -223,6 +224,13 @@ void VersionUpdaterMac::UpdateStatus(NSDictionary* dictionary) {
 }
 
 void VersionUpdaterMac::UpdateShowPromoteButton() {
+  if (ObsoleteSystemMac::Has32BitOnlyCPU() &&
+      ObsoleteSystemMac::Is32BitEndOfTheLine()) {
+    // Promotion is moot upon reaching the end of the line.
+    show_promote_button_ = false;
+    return;
+  }
+
   KeystoneGlue* keystone_glue = [KeystoneGlue defaultKeystoneGlue];
   AutoupdateStatus recent_status = [keystone_glue recentStatus];
   if (recent_status == kAutoupdateRegistering ||