Move AlterEnvironment to base/environment.h, implement on Windows.

chrome/test/chromedriver/chrome_launcher.cc

 // Copyright (c) 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 "chrome/test/chromedriver/chrome_launcher.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/base64.h"
@@ skipping 143 matching lines @@
   Status status = PrepareCommandLine(port, capabilities,
                                      &command, &user_data_dir, &extension_dir);
   if (status.IsError())
     return status;
 
   for (size_t i = 0; i < arraysize(kCommonSwitches); i++)
     command.AppendSwitch(kCommonSwitches[i]);
   base::LaunchOptions options;
 
 #if !defined(OS_WIN)
-  base::EnvironmentVector environ;
-  if (!capabilities.log_path.empty()) {
-    environ.push_back(
-        base::EnvironmentVector::value_type("CHROME_LOG_FILE",
-                                            capabilities.log_path));
-    options.environ = &environ;
-  }
+  if (!capabilities.log_path.empty())
+    options.environ["CHROME_LOG_FILE"] = capabilities.log_path;
   if (capabilities.detach)
     options.new_process_group = true;
 #endif
 
 #if defined(OS_WIN)
   std::string command_string = base::WideToUTF8(command.GetCommandLineString());
 #else
   std::string command_string = command.GetCommandLineString();
 #endif
   log->AddEntry(Log::kLog, "Launching chrome: " + command_string);
@@ skipping 235 matching lines @@
   // Write empty "First Run" file, otherwise Chrome will wipe the default
   // profile that was written.
   if (file_util::WriteFile(
           user_data_dir.AppendASCII("First Run"), "", 0) != 0) {
     return Status(kUnknownError, "failed to write first run file");
   }
   return Status(kOk);
 }
 
 }  // namespace internal