Fix variable shadowing warning in safe_sprintf in VS2015

base/strings/safe_sprintf.cc

 // Copyright 2013 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/strings/safe_sprintf.h"
 
 #include <limits>
 
 #if !defined(NDEBUG)
 // In debug builds, we use RAW_CHECK() to print useful error messages, if
@@ skipping 492 matching lines @@
         const Arg& arg = args[cur_arg++];
         if (arg.type != Arg::INT && arg.type != Arg::UINT) {
           DEBUG_CHECK(arg.type == Arg::INT || arg.type == Arg::UINT);
           goto fail_to_expand;
         }
 
         // Apply padding, if needed.
         buffer.Pad(' ', padding, 1);
 
         // Convert the argument to an ASCII character and output it.
-        char ch = static_cast<char>(arg.integer.i);
-        if (!ch) {
+        char as_char = static_cast<char>(arg.integer.i);
+        if (!as_char) {
           goto end_of_output_buffer;
         }
-        buffer.Out(ch);
+        buffer.Out(as_char);
         break; }
       case 'd':    // Output a possibly signed decimal value.
       case 'o':    // Output an unsigned octal value.
       case 'x':    // Output an unsigned hexadecimal value.
       case 'X':
       case 'p': {  // Output a pointer value.
         // Check that there are arguments left to be inserted.
         if (cur_arg >= max_args) {
           DEBUG_CHECK(cur_arg < max_args);
           goto fail_to_expand;
@@ skipping 148 matching lines @@
     DEBUG_CHECK(src[0] != '%' || src[1] == '%');
     if (src[0] == '%' && src[1] == '%') {
       ++src;
     }
   }
   return buffer.GetCount();
 }
 
 }  // namespace strings
 }  // namespace base