[Webapps]: Clear AppBannerManager::page_requested_prompt_ at start of banner flow

chrome/browser/banners/app_banner_manager.cc

Index: chrome/browser/banners/app_banner_manager.cc
diff --git a/chrome/browser/banners/app_banner_manager.cc b/chrome/browser/banners/app_banner_manager.cc
index 98e0964741bbce168defece1ac6ead560c5f579d..00baa317343fce1d6242067a1fb4e739013c0495 100644
--- a/chrome/browser/banners/app_banner_manager.cc
+++ b/chrome/browser/banners/app_banner_manager.cc
@@ -92,6 +92,8 @@ void AppBannerManager::RequestAppBanner(const GURL& validated_url,
 
   is_active_ = true;
   is_debug_mode_ = is_debug_mode;
+  was_canceled_by_page_ = false;
+  page_requested_prompt_ = false;
 
   // We only need to call ReportStatus if we aren't in debug mode (this avoids
   // skew from testing).
@@ -332,8 +334,6 @@ void AppBannerManager::Stop() {
   event_.reset();
 
   is_active_ = false;
-  was_canceled_by_page_ = false;
-  page_requested_prompt_ = false;
   need_to_log_status_ = false;
 }