[Android]: IPH should be disabled when no experiment.

Minimum engagement score is optional, but, if
there's no experiment data specified, we must
make sure we do not default to 0 engagement score.

The intent was always to disable the feature if
no experiment is specified.

Bug: 1135551
Change-Id: I3cc82f970a7ce1559224ee75335539d298187be4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2614778
Auto-Submit: Finnur Thorarinsson <finnur@chromium.org>
Commit-Queue: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841271}

chrome/browser/banners/android/java/src/org/chromium/chrome/browser/banners/AppBannerManagerTest.java

@@ -793,7 +793,7 @@ public class AppBannerManagerTest {
     @Test
     @MediumTest
     @Feature({"AppBanners"})
-    @CommandLineFlags.Add("enable-features=" + ChromeFeatureList.INSTALLABLE_AMBIENT_BADGE_INFOBAR)
+    @CommandLineFlags.Add("enable-features=" + FeatureConstants.PWA_INSTALL_AVAILABLE_FEATURE)
     public void testInProductHelp() throws Exception {
         // Visit a site that is a PWA. The ambient badge should show.
         String webBannerUrl = WebappTestPage.getServiceWorkerUrl(mTestServer);

chrome/browser/banners/app_banner_manager_android.cc

@@ -452,6 +452,12 @@ base::string16 AppBannerManagerAndroid::GetAppName() const {
 }
 
 bool AppBannerManagerAndroid::MaybeShowInProductHelp() const {
+  if (!base::FeatureList::IsEnabled(
+          feature_engagement::kIPHPwaInstallAvailableFeature)) {
+    DVLOG(2) << "Feature not enabled";
+    return false;
+  }
+
   if (!web_contents()) {
     DVLOG(2) << "IPH for PWA aborted: null WebContents";
     return false;