Update some uses of UTF conversions in chrome/browser to use the base:: namespace.

chrome/browser/spellchecker/spellcheck_message_filter.cc

Index: chrome/browser/spellchecker/spellcheck_message_filter.cc
diff --git a/chrome/browser/spellchecker/spellcheck_message_filter.cc b/chrome/browser/spellchecker/spellcheck_message_filter.cc
index 778f7e3c54ce09b7a6853ad9f2f507b2475da74a..091c342e52da83f8cc1d9e9c0264d06842c097e0 100644
--- a/chrome/browser/spellchecker/spellcheck_message_filter.cc
+++ b/chrome/browser/spellchecker/spellcheck_message_filter.cc
@@ -144,7 +144,7 @@ void SpellCheckMessageFilter::OnTextCheckComplete(
   // in-dictionary feedback.
   std::vector<SpellCheckResult>::iterator write_iter;
   std::vector<SpellCheckResult>::iterator iter;
-  std::string text_copy = UTF16ToUTF8(text);
+  std::string text_copy = base::UTF16ToUTF8(text);
   for (iter = write_iter = results_copy.begin();
        iter != results_copy.end();
        ++iter) {