Standardize StringToInt{,64} interface.

chrome/browser/history/text_database.cc

Index: chrome/browser/history/text_database.cc
diff --git a/chrome/browser/history/text_database.cc b/chrome/browser/history/text_database.cc
index bb70fc75f8e7e0996fcebf26b0e7069af5b51d43..e767cedb01b24149c7ddf281c560e2f1c28ce4eb 100644
--- a/chrome/browser/history/text_database.cc
+++ b/chrome/browser/history/text_database.cc
@@ -12,6 +12,7 @@
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/string_number_conversions.h"
+#include "base/string_piece.h"
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/diagnostics/sqlite_diagnostics.h"
@@ -111,9 +112,14 @@ TextDatabase::DBIdent TextDatabase::FileNameToID(const FilePath& file_path) {
     return 0;
   }
 
+  // TODO: Once StringPiece supports a templated interface over the
+  // underlying string type, use it here instead of substr, since that
+  // will avoid needless string copies.  StringPiece cannot be used
+  // right now because FilePath::StringType could use either 8 or 16 bit
+  // characters, depending on the OS.
   int year, month;
-  base::StringToInt(suffix.begin(), suffix.begin() + 4, &year);
-  base::StringToInt(suffix.begin() + 5, suffix.begin() + 7, &month);
+  base::StringToInt(suffix.substr(0, 4), &year);
+  base::StringToInt(suffix.substr(5, 2), &month);
 
   return year * 100 + month;
 }