Allow app banners to trigger on 0 engagement.

chrome/browser/banners/app_banner_manager.cc

Index: chrome/browser/banners/app_banner_manager.cc
diff --git a/chrome/browser/banners/app_banner_manager.cc b/chrome/browser/banners/app_banner_manager.cc
index 48c676a2f8f0606188ba6003ee20d2fa0ca382dd..2d75eed74428ec31a55b5ba55ac10f448326a0fd 100644
--- a/chrome/browser/banners/app_banner_manager.cc
+++ b/chrome/browser/banners/app_banner_manager.cc
@@ -363,8 +363,12 @@ void AppBannerManager::DidFinishLoad(
 
   load_finished_ = true;
   validated_url_ = validated_url;
+  // Start the pipeline immediately if we aren't using engagement, or if 0
+  // engagement is required.
   if (!AppBannerSettingsHelper::ShouldUseSiteEngagementScore() ||
-      banner_request_queued_) {
+      banner_request_queued_ ||
+      AppBannerSettingsHelper::HasSufficientEngagement(0)) {
+    SiteEngagementObserver::Observe(nullptr);
     banner_request_queued_ = false;
 
     RequestAppBanner(validated_url, false /* is_debug_mode */);