[WebPayments] Implement state transitions in desktop WebPayments dialog.

chrome/browser/ui/BUILD.gn

Index: chrome/browser/ui/BUILD.gn
diff --git a/chrome/browser/ui/BUILD.gn b/chrome/browser/ui/BUILD.gn
index d4cf8b03479927f9861765cb14fecaebd6a37aad..c77fd27a82b30db5072fefa26205de8af84ff638 100644
--- a/chrome/browser/ui/BUILD.gn
+++ b/chrome/browser/ui/BUILD.gn
@@ -1790,8 +1790,18 @@ split_static_library("ui") {
         "views/passwords/manage_passwords_bubble_view.h",
         "views/passwords/manage_passwords_icon_views.cc",
         "views/passwords/manage_passwords_icon_views.h",
+        "views/payments/order_summary_state.cc",
+        "views/payments/order_summary_state.h",
+        "views/payments/order_summary_state_observer.h",
         "views/payments/payment_request_dialog.cc",
         "views/payments/payment_request_dialog.h",
+        "views/payments/payment_sheet_state.cc",
+        "views/payments/payment_sheet_state.h",
+        "views/payments/payment_sheet_state_observer.h",
+        "views/payments/view_stack.cc",
+        "views/payments/view_stack.h",
+        "views/payments/view_stack_state.cc",
+        "views/payments/view_stack_state.h",
         "views/process_singleton_dialog_linux.cc",
         "views/profiles/profile_indicator_icon.cc",
         "views/profiles/profile_indicator_icon.h",