Add a method for normalizing path separators on Windows.

base/file_path.cc

Index: base/file_path.cc
diff --git a/base/file_path.cc b/base/file_path.cc
index d1a6371ceb1cd9a168da2d1f7d545ac935fc3082..0706a08ecda79f4e496e062a11c411b65fad0ca3 100644
--- a/base/file_path.cc
+++ b/base/file_path.cc
@@ -1124,3 +1124,12 @@ bool FilePath::ReferencesParent() const {
   return false;
 }
 
+#if defined(FILE_PATH_USES_WIN_SEPARATORS)
+FilePath FilePath::NormalizeWindowsPathSeparators() const {
+  StringType copy = path_;
+  for (size_t i = 1; i < arraysize(kSeparators); ++i) {
+    std::replace(copy.begin(), copy.end(), kSeparators[i], kSeparators[0]);
+  }
+  return FilePath(copy);
+}
+#endif