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 7e36595b10047ce7207c1b4a0240fa9f6125fb4a..82dd2abcec620d56bc623991ba98c738d1a3fb07 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"
@@ -130,6 +131,8 @@ 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_;