[Payments] Add the pay button, and control its enabled state

chrome/browser/payments/chrome_payment_request_delegate.cc

Index: chrome/browser/payments/chrome_payment_request_delegate.cc
diff --git a/chrome/browser/payments/chrome_payment_request_delegate.cc b/chrome/browser/payments/chrome_payment_request_delegate.cc
index 919fd5399db2c47d4876bbffd3af3c15eabaf72c..7b228b62ad454ad055b80c06275f99d5162df4e4 100644
--- a/chrome/browser/payments/chrome_payment_request_delegate.cc
+++ b/chrome/browser/payments/chrome_payment_request_delegate.cc
@@ -6,6 +6,7 @@
 
 #include "base/macros.h"
 #include "chrome/browser/autofill/personal_data_manager_factory.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_dialogs.h"
 #include "components/payments/content/payment_request_dialog.h"
@@ -36,4 +37,8 @@ ChromePaymentRequestDelegate::GetPersonalDataManager() {
       Profile::FromBrowserContext(web_contents_->GetBrowserContext()));
 }
 
+const std::string& ChromePaymentRequestDelegate::GetApplicationLocale() const {
+  return g_browser_process->GetApplicationLocale();
+}
+
 }  // namespace payments