Trigger app banner when add to homescreen is pressed and WebAPKs are enabled.

chrome/browser/android/webapps/add_to_homescreen_manager.h

Index: chrome/browser/android/webapps/add_to_homescreen_manager.h
diff --git a/chrome/browser/android/webapps/add_to_homescreen_manager.h b/chrome/browser/android/webapps/add_to_homescreen_manager.h
index 7ab90b5376eb5cdaec74250212a019b49a0c099d..d97b72cf5927c98f063764fa38021d18c14d2ef3 100644
--- a/chrome/browser/android/webapps/add_to_homescreen_manager.h
+++ b/chrome/browser/android/webapps/add_to_homescreen_manager.h
@@ -68,6 +68,10 @@ class AddToHomescreenManager : public AddToHomescreenDataFetcher::Observer {
   // data needed to add the shortcut.
   void AddShortcut(const ShortcutInfo& info, const SkBitmap& icon);
 
+  // Called only when the AddToHomescreenDataFetcher has retrieved all of the
+  // data needed to install a WebAPK.
+  void CreateInfoBarForWebAPK(const ShortcutInfo& info, const SkBitmap& icon);
+
   void RecordAddToHomescreen();
 
   // AddToHomescreenDataFetcher::Observer:
@@ -85,6 +89,9 @@ class AddToHomescreenManager : public AddToHomescreenDataFetcher::Observer {
   // in progress.
   bool add_shortcut_pending_;
 
+  // Whether the site is WebAPK-compatible.
+  bool is_webapk_compatible_;
+
   // Fetches data required to add a shortcut.
   scoped_refptr<AddToHomescreenDataFetcher> data_fetcher_;