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

components/autofill/core/browser/autofill_external_delegate.cc

Index: components/autofill/core/browser/autofill_external_delegate.cc
diff --git a/components/autofill/core/browser/autofill_external_delegate.cc b/components/autofill/core/browser/autofill_external_delegate.cc
index c4367567ff274c7801e20dea6ef5f0dd89111e21..0fb86c6d14eefad318196c0a40de1c4802982f65 100644
--- a/components/autofill/core/browser/autofill_external_delegate.cc
+++ b/components/autofill/core/browser/autofill_external_delegate.cc
@@ -13,6 +13,7 @@
 #include "ui/base/l10n/l10n_util.h"
 
 using blink::WebAutofillClient;
+using base::ASCIIToUTF16;
 
 namespace autofill {
 
@@ -172,6 +173,15 @@ void AutofillExternalDelegate::DidSelectSuggestion(int identifier) {
     FillAutofillFormData(identifier, true);
 }
 
+void AutofillExternalDelegate::DidSelectAutocompleteSuggestion(
+    const base::string16& value) {
+  ClearPreviewedForm();
+  ClearAutocompletePreviewedField();
+
+  // Preview the data if it is in an AutoComplete field.
+  autofill_driver_->RendererShouldSetNodeText(value);

[Ilya Sherman, 2014/02/14 02:22:28]

This is incorrect.  The renderer should preview the text, not set it.  The
difference is essentially in whether the change is visible to JavaScript, though
this also makes it easier to restore the previous value prior to mouse-hover.

+}
+
 void AutofillExternalDelegate::DidAcceptSuggestion(const base::string16& value,
                                                    int identifier) {
   if (identifier == WebAutofillClient::MenuItemIDAutofillOptions) {
@@ -216,6 +226,10 @@ void AutofillExternalDelegate::ClearPreviewedForm() {
   autofill_driver_->RendererShouldClearPreviewedForm();
 }
 
+void AutofillExternalDelegate::ClearAutocompletePreviewedField() {
+  autofill_driver_->RendererShouldSetNodeText(ASCIIToUTF16(""));

[Ilya Sherman, 2014/02/14 02:22:28]

This is incorrect.  The field value shouldn't be cleared; it should return to
whatever it was prior to being previewed.

+}
+
 void AutofillExternalDelegate::Reset() {
   autofill_manager_->delegate()->HideAutofillPopup();