Allow the app banner installability check to run on page load.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index e09546cdb00a1f6f48699f642b00101ae3b64535..989c2ff18a56509f2617fd13da47aac9b5ca57e1 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -76819,6 +76819,25 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Webapp.InstallabilityCheckStatus.MenuItemAddToHomescreen"
+    enum="InstallabilityCheckStatus">
+  <owner>dominickn@chromium.org</owner>
+  <summary>
+    Records whether or not the check that a site is or isn't a Progressive Web
+    App (PWA) has completed when the user taps the add to homescreen menu item
+    on Android.
+  </summary>
+</histogram>
+
+<histogram name="Webapp.InstallabilityCheckStatus.MenuOpen"
+    enum="InstallabilityCheckStatus">
+  <owner>dominickn@chromium.org</owner>
+  <summary>
+    Records whether or not the check that a site is or isn't a Progressive Web
+    App (PWA) has completed when the user opens the menu on Android.
+  </summary>
+</histogram>
+
 <histogram name="Webapp.Splashscreen.BackgroundColor"
     enum="SplashscreenColorStatus">
   <owner>mlamouri@chromium.org</owner>
@@ -98262,6 +98281,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="35" label="Ran by google.com/intl/ (deprecated)"/>
 </enum>
 
+<enum name="InstallabilityCheckStatus" type="int">
+  <int value="0" label="Check not started"/>
+  <int value="1" label="Check terminated before it could finish"/>
+  <int value="2" label="Check not complete, site is not a PWA"/>
+  <int value="3" label="Check not complete, site is a PWA"/>
+  <int value="4" label="Check complete, site is not a PWA"/>
+  <int value="5" label="Check complete, site is a PWA"/>
+</enum>
+
 <enum name="InstallStatus" type="int">
   <int value="0" label="FIRST_INSTALL_SUCCESS"/>
   <int value="1" label="INSTALL_REPAIRED"/>