Fail autocheckout if there is no forms in the page.

chrome/browser/ui/autofill/tab_autofill_manager_delegate.cc

Index: chrome/browser/ui/autofill/tab_autofill_manager_delegate.cc
diff --git a/chrome/browser/ui/autofill/tab_autofill_manager_delegate.cc b/chrome/browser/ui/autofill/tab_autofill_manager_delegate.cc
index 80d6c1353d72cbc9eb23258f66b054f66d67b0bd..38edf3cb143a38387dc9377849ea8fefceb0e881 100644
--- a/chrome/browser/ui/autofill/tab_autofill_manager_delegate.cc
+++ b/chrome/browser/ui/autofill/tab_autofill_manager_delegate.cc
@@ -98,6 +98,8 @@ void TabAutofillManagerDelegate::SetSyncStateChangedCallback(
 }
 
 void TabAutofillManagerDelegate::OnAutocheckoutError() {
+  // |dialog_controller_| is a WeakPtr, but we require it to be present when
+  // |OnAutocheckoutError| is called, so we intentionally do not do NULL check.
   dialog_controller_->OnAutocheckoutError();
 }
 
@@ -199,6 +201,8 @@ void TabAutofillManagerDelegate::HideAutofillPopup() {
 }
 
 void TabAutofillManagerDelegate::UpdateProgressBar(double value) {
+  // |dialog_controller_| is a WeakPtr, but we require it to be present when
+  // |UpdateProgressBar| is called, so we intentionally do not do NULL check.
   dialog_controller_->UpdateProgressBar(value);
 }