[Omnibox] Clean up comment, don't ref closed bugs.

chrome/browser/autocomplete/autocomplete_controller.cc

Index: chrome/browser/autocomplete/autocomplete_controller.cc
diff --git a/chrome/browser/autocomplete/autocomplete_controller.cc b/chrome/browser/autocomplete/autocomplete_controller.cc
index 82549005f91c24fc0c63fc89c8f5681599f98517..552a429aea393576aba4dca3c05ba65454aa135d 100644
--- a/chrome/browser/autocomplete/autocomplete_controller.cc
+++ b/chrome/browser/autocomplete/autocomplete_controller.cc
@@ -258,8 +258,7 @@ void AutocompleteController::Start(const AutocompleteInput& input) {
   in_start_ = true;
   base::TimeTicks start_time = base::TimeTicks::Now();
   for (Providers::iterator i(providers_.begin()); i != providers_.end(); ++i) {
-    // TODO(mpearson): Remove timing code once bugs 178705 / 237703 / 168933
-    // are resolved.
+    // TODO(mpearson): Remove timing code once bug 178705 is resolved.
     base::TimeTicks provider_start_time = base::TimeTicks::Now();
     (*i)->Start(input_, minimal_changes, false);
     if (!input.want_asynchronous_matches())