Add "previewing on hover" support for single-field autocomplete input

components/autofill/core/browser/autofill_external_delegate.h

Index: components/autofill/core/browser/autofill_external_delegate.h
diff --git a/components/autofill/core/browser/autofill_external_delegate.h b/components/autofill/core/browser/autofill_external_delegate.h
index e399eb580044e3ab81d2cc31e9ee4a1ba6be3c51..0d5a58e9d6003a53010a062343c2676058ddc45f 100644
--- a/components/autofill/core/browser/autofill_external_delegate.h
+++ b/components/autofill/core/browser/autofill_external_delegate.h
@@ -45,11 +45,14 @@ class AutofillExternalDelegate
   virtual void OnPopupHidden() OVERRIDE;
   virtual bool ShouldRepostEvent(const ui::MouseEvent& event) OVERRIDE;
   virtual void DidSelectSuggestion(int identifier) OVERRIDE;
+  virtual void
+      DidSelectAutocompleteSuggestion(const base::string16& value) OVERRIDE;
   virtual void DidAcceptSuggestion(const base::string16& value,
                                    int identifier) OVERRIDE;
   virtual void RemoveSuggestion(const base::string16& value,
                                 int identifier) OVERRIDE;
   virtual void ClearPreviewedForm() OVERRIDE;
+  virtual void ClearAutocompletePreviewedField() OVERRIDE;
 
   // Records and associates a query_id with web form data.  Called
   // when the renderer posts an Autofill query to the browser. |bounds|