Add WebAPK installation metrics.

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 6e09f1b5ad2a846be7a6aa4ef067bb33bc59dabd..07b2a9afdf1ceeb61da1d949ef775710c658fe7c 100644
--- a/chrome/browser/android/banners/app_banner_infobar_delegate_android.h
+++ b/chrome/browser/android/banners/app_banner_infobar_delegate_android.h
@@ -9,6 +9,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string16.h"
+#include "chrome/browser/android/webapk/webapk_metrics.h"
 #include "chrome/browser/banners/app_banner_manager.h"
 #include "components/infobars/core/confirm_infobar_delegate.h"
 #include "ui/gfx/image/image.h"
@@ -132,6 +133,8 @@ class AppBannerInfoBarDelegateAndroid : public ConfirmInfoBarDelegate {
 
   std::string webapk_package_name_;
   bool is_webapk_;
+  // Indicates the current state of a WebAPK installation.
+  webapk::InstallState install_state_;
 
   base::WeakPtrFactory<AppBannerInfoBarDelegateAndroid> weak_ptr_factory_;