Move EmptyString, kWhitespace and the BOM to base.

chrome/browser/history/url_index_private_data.cc

Index: chrome/browser/history/url_index_private_data.cc
diff --git a/chrome/browser/history/url_index_private_data.cc b/chrome/browser/history/url_index_private_data.cc
index bbb8aae4fe91c9cd18d6e6d9c75d3a6e7d93081e..b7d9c3715e18ed63c3acf1d50f9c84ca4a64684f 100644
--- a/chrome/browser/history/url_index_private_data.cc
+++ b/chrome/browser/history/url_index_private_data.cc
@@ -234,7 +234,8 @@ ScoredHistoryMatches URLIndexPrivateData::HistoryItemsForTerms(
   // escaped whitespace. When the user types "colspec=ID%20Mstone Release" we
   // get two 'terms': "colspec=id%20mstone" and "release".
   history::String16Vector lower_raw_terms;
-  if (Tokenize(lower_raw_string, kWhitespaceUTF16, &lower_raw_terms) == 0) {
+  if (Tokenize(lower_raw_string, base::kWhitespaceUTF16,
+               &lower_raw_terms) == 0) {
     // Don't score matches when there are no terms to score against.  (It's
     // possible that the word break iterater that extracts words to search
     // for in the database allows some whitespace "words" whereas Tokenize