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

chrome/browser/android/banners/app_banner_infobar_delegate_android.h

Index: chrome/browser/android/banners/app_banner_infobar_delegate_android.h
diff --git a/chrome/browser/android/banners/app_banner_infobar_delegate_android.h b/chrome/browser/android/banners/app_banner_infobar_delegate_android.h
index c78aa8def8af41f30db46695348dfc8db65437ab..19969cdd9e3059323d0ee8865c0936951677f5ac 100644
--- a/chrome/browser/android/banners/app_banner_infobar_delegate_android.h
+++ b/chrome/browser/android/banners/app_banner_infobar_delegate_android.h
@@ -24,6 +24,7 @@ class InfoBarManager;
 }
 
 class AppBannerInfoBar;
+struct ShortcutInfo;
 
 namespace banners {
 
@@ -35,7 +36,7 @@ class AppBannerInfoBarDelegateAndroid : public ConfirmInfoBarDelegate {
       base::WeakPtr<AppBannerManager> weak_manager,
       const base::string16& app_title,
       const GURL& manifest_url,
-      const content::Manifest& manifest,
+      std::unique_ptr<ShortcutInfo> info,
       const GURL& icon_url,
       std::unique_ptr<SkBitmap> icon,
       int event_request_id,
@@ -67,6 +68,12 @@ class AppBannerInfoBarDelegateAndroid : public ConfirmInfoBarDelegate {
                          const base::android::JavaParamRef<jobject>& obj,
                          jboolean success);
 
+  // Called when user clicks the "Add To Home screen" from the app menu to
+  // install a WebAPK. The banner skips the state of showing "Add To
+  // Homescreen" on the button and jumps to the state of showing "Adding"
+  // and starts the installation.
+  void InstallWebApk(content::WebContents* web_contents);
+
  private:
   void CreateJavaDelegate();
   bool AcceptNativeApp(content::WebContents* web_contents);
@@ -92,7 +99,7 @@ class AppBannerInfoBarDelegateAndroid : public ConfirmInfoBarDelegate {
 
   base::string16 app_title_;
   GURL manifest_url_;
-  content::Manifest manifest_;
+  std::unique_ptr<ShortcutInfo> info_;
 
   base::android::ScopedJavaGlobalRef<jobject> native_app_data_;