GN: Move towards only using / on Windows

base/files/file_path.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/files/file_path.h"
 
 #include <string.h>
 #include <algorithm>
 
 #include "base/basictypes.h"
@@ skipping 1274 matching lines @@
     // don't strip them, unless the string began with more than two separators.
     if (pos != start + 1 || last_stripped == start + 2 ||
         !IsSeparator(path_[start - 1])) {
       path_.resize(pos - 1);
       last_stripped = pos;
     }
   }
 }
 
 FilePath FilePath::NormalizePathSeparators() const {
+  return NormalizePathSeparatorsTo(kSeparators[0]);
+}
+
+FilePath FilePath::NormalizePathSeparatorsTo(CharType separator) const {
 #if defined(FILE_PATH_USES_WIN_SEPARATORS)
+  DCHECK_NE(kSeparators + kSeparatorsLength,
+            std::find(kSeparators, kSeparators + kSeparatorsLength, separator));
   StringType copy = path_;
-  for (size_t i = 1; i < kSeparatorsLength; ++i) {
-    std::replace(copy.begin(), copy.end(), kSeparators[i], kSeparators[0]);
+  for (size_t i = 0; i < kSeparatorsLength; ++i) {
+    std::replace(copy.begin(), copy.end(), kSeparators[i], separator);
   }
   return FilePath(copy);
 #else
   return *this;
 #endif
 }
 
 #if defined(OS_ANDROID)
 bool FilePath::IsContentUri() const {
   return StartsWithASCII(path_, "content://", false /*case_sensitive*/);
 }
 #endif
 
 }  // namespace base
 
 void PrintTo(const base::FilePath& path, std::ostream* out) {
   *out << path.value();
 }