GTK: Implement BlockedPopupContainerView for linux.

base/string_util.cc

Index: base/string_util.cc
diff --git a/base/string_util.cc b/base/string_util.cc
index 2998d2b36f4a80672ed865b0cf73b318e60c0595..2699f26833b835b0d0a90d7ba9c0921c92b7e085 100644
--- a/base/string_util.cc
+++ b/base/string_util.cc
@@ -1061,6 +1061,10 @@ std::wstring UintToWString(unsigned int value) {
   return IntToStringT<std::wstring, unsigned int, unsigned int, false>::
       IntToString(value);
 }
+string16 UintToString16(unsigned int value) {
+  return IntToStringT<string16, unsigned int, unsigned int, false>::
+      IntToString(value);
+}
 std::string Int64ToString(int64 value) {
   return IntToStringT<std::string, int64, uint64, true>::
       IntToString(value);