Fixing some warning due to different signess of char

base/string_split.cc

 // Copyright (c) 2011 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/string_split.h"
 
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "base/third_party/icu/icu_utf.h"
 #include "base/utf_string_conversions.h"
@@ skipping 27 matching lines @@
 void SplitString(const string16& str,
                  char16 c,
                  std::vector<string16>* r) {
   DCHECK(CBU16_IS_SINGLE(c));
   SplitStringT(str, c, true, r);
 }
 
 void SplitString(const std::string& str,
                  char c,
                  std::vector<std::string>* r) {
-  DCHECK(c >= 0 && c < 0x7F);
+#if CHAR_MIN < 0
+  DCHECK(c >= 0);
+#endif
+  DCHECK(c < 0x7F);
   SplitStringT(str, c, true, r);
 }
 
 bool SplitStringIntoKeyValues(
     const std::string& line,
     char key_value_delimiter,
     std::string* key, std::vector<std::string>* values) {
   key->clear();
   values->clear();
 
@@ skipping 90 matching lines @@
                          char16 c,
                          std::vector<string16>* r) {
   DCHECK(CBU16_IS_SINGLE(c));
   SplitStringT(str, c, false, r);
 }
 
 void SplitStringDontTrim(const std::string& str,
                          char c,
                          std::vector<std::string>* r) {
   DCHECK(IsStringUTF8(str));
-  DCHECK(c >= 0 && c < 0x7F);
+#if CHAR_MIN < 0
+  DCHECK(c >= 0);
+#endif
+  DCHECK(c < 0x7F);
   SplitStringT(str, c, false, r);
 }
 
 template<typename STR>
 void SplitStringAlongWhitespaceT(const STR& str, std::vector<STR>* result) {
   const size_t length = str.length();
   if (!length)
     return;
 
   bool last_was_ws = false;
@@ skipping 34 matching lines @@
                                 std::vector<string16>* result) {
   SplitStringAlongWhitespaceT(str, result);
 }
 
 void SplitStringAlongWhitespace(const std::string& str,
                                 std::vector<std::string>* result) {
   SplitStringAlongWhitespaceT(str, result);
 }
 
 }  // namespace base