Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/stubs/strutil.cc

Index: third_party/protobuf/src/google/protobuf/stubs/strutil.cc
diff --git a/third_party/protobuf/src/google/protobuf/stubs/strutil.cc b/third_party/protobuf/src/google/protobuf/stubs/strutil.cc
index 15b6e53f1a648ab38e09bf77c346f94a739847f8..7ba92e8f1fa4d95dd77feb4a14abe6aa1326c1b7 100644
--- a/third_party/protobuf/src/google/protobuf/stubs/strutil.cc
+++ b/third_party/protobuf/src/google/protobuf/stubs/strutil.cc
@@ -93,21 +93,6 @@ void StripString(string* s, const char* remove, char replacewith) {
   }
 }
 
-// ----------------------------------------------------------------------
-// ReplaceCharacters
-//    Replaces any occurrence of the character 'remove' (or the characters
-//    in 'remove') with the character 'replacewith'.
-// ----------------------------------------------------------------------
-void ReplaceCharacters(string *s, const char *remove, char replacewith) {
-  const char *str_start = s->c_str();
-  const char *str = str_start;
-  for (str = strpbrk(str, remove);
-       str != NULL;
-       str = strpbrk(str + 1, remove)) {
-    (*s)[str - str_start] = replacewith;
-  }
-}
-
 void StripWhitespace(string* str) {
   int str_length = str->length();
 
@@ -981,7 +966,7 @@ static const char two_ASCII_digits[100][2] = {
 };
 
 char* FastUInt32ToBufferLeft(uint32 u, char* buffer) {
-  uint32 digits;
+  int digits;
   const char *ASCII_digits = NULL;
   // The idea of this implementation is to trim the number of divides to as few
   // as possible by using multiplication and subtraction rather than mod (%),