Implement experimental app banner flow.

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 9524f7eff2093ecb1489a53631f279852a4d1392..7d26790a08dcfd067de6f2cacb2c4e8d2035c0f3 100644
--- a/chrome/browser/banners/app_banner_manager.cc
+++ b/chrome/browser/banners/app_banner_manager.cc
@@ -405,10 +405,12 @@ void AppBannerManager::DidFinishLoad(
     has_sufficient_engagement_ = true;
 
   // Start the pipeline immediately if we pass (or bypass) the engagement check,
-  // or if the feature to run the installability check on page load is enabled.
+  // or if the feature to run the installability check on page load is enabled,
+  // or if the experimental banner flow is enabled.
   if (has_sufficient_engagement_ ||
       base::FeatureList::IsEnabled(
-          features::kCheckInstallabilityForBannerOnLoad)) {
+          features::kCheckInstallabilityForBannerOnLoad) ||
+      IsExperimentalAppBannersEnabled()) {
     RequestAppBanner(validated_url, false /* is_debug_mode */);
   }
 }
@@ -459,6 +461,11 @@ void AppBannerManager::OnEngagementIncreased(content::WebContents* contents,
   }
 }
 
+// static
+bool AppBannerManager::IsExperimentalAppBannersEnabled() {
+  return base::FeatureList::IsEnabled(features::kExperimentalAppBanners);
+}
+
 void AppBannerManager::RecordCouldShowBanner() {
   content::WebContents* contents = web_contents();
   DCHECK(contents);
@@ -514,7 +521,6 @@ void AppBannerManager::OnBannerPromptReply(
   // We don't need the controller any more, so reset it so the Blink-side object
   // is destroyed.
   controller_.reset();
-  content::WebContents* contents = web_contents();
 
   // The renderer might have requested the prompt to be canceled. They may
   // request that it is redisplayed later, so don't Stop() here. However, log
@@ -525,13 +531,19 @@ void AppBannerManager::OnBannerPromptReply(
   // request may be received *before* the Cancel prompt reply (e.g. if redisplay
   // is requested in the beforeinstallprompt event handler).
   referrer_ = referrer;
-  if (reply == blink::mojom::AppBannerPromptReply::CANCEL) {
+  if (IsExperimentalAppBannersEnabled() ||
+      reply == blink::mojom::AppBannerPromptReply::CANCEL) {
     UpdateState(State::PENDING_EVENT);
     TrackBeforeInstallEvent(BEFORE_INSTALL_EVENT_PREVENT_DEFAULT_CALLED);
     if (!page_requested_prompt_)
       return;
   }
 
+  if (!IsExperimentalAppBannersEnabled())
+    ShowBanner();
+}
+
+void AppBannerManager::ShowBanner() {
   // If we haven't yet returned, but we're in the PENDING_EVENT state or
   // |page_requested_prompt_| is true, the page has requested a delayed showing
   // of the prompt. Otherwise, the prompt was never canceled by the page.
@@ -541,8 +553,12 @@ void AppBannerManager::OnBannerPromptReply(
     UpdateState(State::ACTIVE);
   } else {
     TrackBeforeInstallEvent(BEFORE_INSTALL_EVENT_NO_ACTION);
+    // In the experimental flow, the banner is only shown if the site explicitly
+    // requests it to be shown.
+    DCHECK(!IsExperimentalAppBannersEnabled());
   }
 
+  content::WebContents* contents = web_contents();
   AppBannerSettingsHelper::RecordMinutesFromFirstVisitToShow(
       contents, validated_url_, GetAppIdentifier(), GetCurrentTime());
 
@@ -552,14 +568,21 @@ void AppBannerManager::OnBannerPromptReply(
   DCHECK(!primary_icon_.drawsNothing());
 
   TrackBeforeInstallEvent(BEFORE_INSTALL_EVENT_COMPLETE);
-  ShowBanner();
+  ShowBannerUI();
   UpdateState(State::COMPLETE);
 }
 
 void AppBannerManager::DisplayAppBanner(bool user_gesture) {
+  // In the experimental flow, a user gesture is required for the prompt to be
+  // shown.
+  if (IsExperimentalAppBannersEnabled() && !user_gesture) {
+    // TODO: do some logging / error here
+    return;
+  }
+
   if (is_pending_event()) {
     // Simulate a non-canceled OnBannerPromptReply to show the delayed banner.
-    OnBannerPromptReply(blink::mojom::AppBannerPromptReply::NONE, referrer_);
+    ShowBanner();
   } else {
     // Log that the prompt request was made for when we get the prompt reply.
     page_requested_prompt_ = true;