Remove redundant c_str() calls.

base/environment.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/environment.h"
 
 #include <stddef.h>
 
 #include <vector>
 
@@ skipping 24 matching lines @@
     // and look for a variable name with the reverse case.
     // I.e. HTTP_PROXY may be http_proxy for some users/systems.
     char first_char = variable_name[0];
     std::string alternate_case_var;
     if (IsAsciiLower(first_char))
       alternate_case_var = ToUpperASCII(variable_name);
     else if (IsAsciiUpper(first_char))
       alternate_case_var = ToLowerASCII(variable_name);
     else
       return false;
-    return GetVarImpl(alternate_case_var.c_str(), result);
+    return GetVarImpl(alternate_case_var, result);
   }
 
   bool SetVar(StringPiece variable_name,
               const std::string& new_value) override {
     return SetVarImpl(variable_name, new_value);
   }
 
   bool UnSetVar(StringPiece variable_name) override {
     return UnSetVarImpl(variable_name);
   }
@@ skipping 175 matching lines @@
   for (size_t i = 0; i < result_indices.size(); i++)
     result[i] = &storage_data[result_indices[i]];
   result[result_indices.size()] = 0;  // Null terminator.
 
   return result;
 }
 
 #endif  // OS_POSIX
 
 }  // namespace base