[Autofill] Add UMA timing metrics for requestAutocomplete dialog.

chrome/browser/autofill/autocheckout_infobar_delegate.h

Index: chrome/browser/autofill/autocheckout_infobar_delegate.h
diff --git a/chrome/browser/autofill/autocheckout_infobar_delegate.h b/chrome/browser/autofill/autocheckout_infobar_delegate.h
index 60c82f437cfea52fdb706341a86f714123560ce9..34c21e8c69e66465d91e4a387cc846d95f709b4a 100644
--- a/chrome/browser/autofill/autocheckout_infobar_delegate.h
+++ b/chrome/browser/autofill/autocheckout_infobar_delegate.h
@@ -14,12 +14,14 @@
 #include "content/public/common/ssl_status.h"
 #include "googleurl/src/gurl.h"
 
-class AutocheckoutManager;
-
 namespace content {
 struct LoadCommittedDetails;
 }
 
+namespace autofill {
+
+class AutocheckoutManager;
+
 // An InfoBar delegate that enables the user to allow or deny storing credit
 // card information gathered from a form submission.
 class AutocheckoutInfoBarDelegate : public ConfirmInfoBarDelegate {
@@ -88,4 +90,6 @@ class AutocheckoutInfoBarDelegate : public ConfirmInfoBarDelegate {
   DISALLOW_COPY_AND_ASSIGN(AutocheckoutInfoBarDelegate);
 };
 
+}  // namespace autofill
+
 #endif  // CHROME_BROWSER_AUTOFILL_AUTOCHECKOUT_INFOBAR_DELEGATE_H_