[Autofill] Add UMA timing metrics for requestAutocomplete dialog.

chrome/browser/autofill/autofill_manager_delegate.h

Index: chrome/browser/autofill/autofill_manager_delegate.h
diff --git a/chrome/browser/autofill/autofill_manager_delegate.h b/chrome/browser/autofill/autofill_manager_delegate.h
index 019f36d53d14a6457a636cc6c0ced199cc9694d8..62d81cd9134fa6178a7a14b8f9d6339155c1b427 100644
--- a/chrome/browser/autofill/autofill_manager_delegate.h
+++ b/chrome/browser/autofill/autofill_manager_delegate.h
@@ -21,6 +21,7 @@ namespace gfx {
 class Rect;
 }
 
+class AutofillMetrics;
 class FormStructure;
 class GURL;
 class InfoBarService;
@@ -32,6 +33,13 @@ struct FormData;
 
 namespace autofill {
 
+enum DialogRequester {
+  // Requested by the Autocheckout feature.
+  DIALOG_REQUESTER_AUTOCHECKOUT,
+  // Requested by the requestAutocomplete feature.
+  DIALOG_REQUESTER_REQUEST_AUTOCOMPLETE,
+};
+
 // A delegate interface that needs to be supplied to AutofillManager
 // by the embedder.
 //
@@ -83,6 +91,8 @@ class AutofillManagerDelegate {
       const FormData& form,
       const GURL& source_url,
       const content::SSLStatus& ssl_status,
+      const AutofillMetrics& metric_logger,
+      DialogRequester requester,
       const base::Callback<void(const FormStructure*)>& callback) = 0;
 
   // Called when the dialog for request autocomplete closes.