Update upgrade app menu icons for MD/vectorization.

chrome/browser/upgrade_detector.h

Index: chrome/browser/upgrade_detector.h
diff --git a/chrome/browser/upgrade_detector.h b/chrome/browser/upgrade_detector.h
index 7dcbf3657f35cc63c81f43ff48886a704899144f..58a8c0e9d364321cf9e02f92dab7e82365685347 100644
--- a/chrome/browser/upgrade_detector.h
+++ b/chrome/browser/upgrade_detector.h
@@ -70,10 +70,10 @@ class UpgradeDetector {
 
   bool is_factory_reset_required() const { return is_factory_reset_required_; }
 
-  // Retrieves the right icon ID based on the degree of severity (see
+  // Retrieves the right icon based on the degree of severity (see
   // UpgradeNotificationAnnoyanceLevel, each level has an an accompanying icon
   // to go with it) to display within the app menu.
-  int GetIconResourceID();
+  gfx::Image GetIcon();
 
   UpgradeNotificationAnnoyanceLevel upgrade_notification_stage() const {
     return upgrade_notification_stage_;