cocoa: allow omnibox decorations to become key

chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_cell.mm

Index: chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_cell.mm
diff --git a/chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_cell.mm b/chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_cell.mm
index fade6898f5157e459a726971b385b76c09c53089..e09ee0d517737e9da1027f40134298b071d15dad 100644
--- a/chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_cell.mm
+++ b/chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_cell.mm
@@ -736,6 +736,13 @@ - (void)handleFocusEvent:(NSEvent*)event
   }
 }
 
+- (int)leadingDecorationIndex:(LocationBarDecoration*)decoration {
+  for (size_t i = 0; i < leadingDecorations_.size(); ++i)

[Mark Mentovai, 2017/04/25 20:44:31]

I like to use std::find and std::distance for this kind of thing, but you’re
free to ignore the suggestion. Some people like the explicit loop better, and
that’s OK too.

[Elly Fong-Jones, 2017/04/26 16:50:01]

I prefer the explicit loop, but I'm not quite sure why.

+    if (leadingDecorations_[i] == decoration)
+      return leadingDecorations_.size() - (i + 1);
+  return -1;
+}
+
 @end
 
 @implementation AutocompleteTextFieldCell (TestingAPI)