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

chrome/browser/ui/autofill/autofill_popup_controller_impl.cc

Index: chrome/browser/ui/autofill/autofill_popup_controller_impl.cc
diff --git a/chrome/browser/ui/autofill/autofill_popup_controller_impl.cc b/chrome/browser/ui/autofill/autofill_popup_controller_impl.cc
index e7cc9dd6b46a241a090f50647f025f7c66854df6..d4d3d99b94cbce95d21d715b35e3a16b5fcbf678 100644
--- a/chrome/browser/ui/autofill/autofill_popup_controller_impl.cc
+++ b/chrome/browser/ui/autofill/autofill_popup_controller_impl.cc
@@ -446,10 +446,17 @@ void AutofillPopupControllerImpl::SetSelectedLine(int selected_line) {
 
   selected_line_ = selected_line;
 
-  if (selected_line_ != kNoSelection)
-    delegate_->DidSelectSuggestion(identifiers_[selected_line_]);
-  else
+  if (selected_line_ != kNoSelection) {
+    if ((identifiers_[selected_line_] ==
+         WebAutofillClient::MenuItemIDAutocompleteEntry) &&
+        (selected_line_ < static_cast<int>(names_.size())))

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

nit: No need for the extra parens around the components of the conditional
expression in this if-stmt.

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

Why do you need the second check?  When can selected_line_ be out-of-bounds?

+      delegate_->DidSelectAutocompleteSuggestion(names_[selected_line_]);

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

Rather than introducing a new method, it seems reasonable to parallel
DidAcceptSugestion(), which takes both the value and the identifier as a
parameter.

+    else
+      delegate_->DidSelectSuggestion(identifiers_[selected_line_]);
+  } else {
     delegate_->ClearPreviewedForm();
+    delegate_->ClearAutocompletePreviewedField();

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

Why can't ClearPreviewedForm() just handle clearing all previews?

+  }
 }
 
 void AutofillPopupControllerImpl::SelectNextLine() {
@@ -520,6 +527,7 @@ bool AutofillPopupControllerImpl::RemoveSelectedLine() {
 
   if (HasSuggestions()) {
     delegate_->ClearPreviewedForm();
+    delegate_->ClearAutocompletePreviewedField();
     UpdateBoundsAndRedrawPopup();
   } else {
     Hide();