iwyu: Cleanup in the following files:

base/base_paths_linux.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/base_paths.h"
 
-#include <unistd.h>
-#if defined(OS_FREEBSD)
-#include <sys/param.h>
-#include <sys/sysctl.h>
-#endif
+#include <ostream>
+#include <string>
 
+#include "build/build_config.h"
 #include "base/environment.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
-#include "base/sys_string_conversions.h"
 #include "base/nix/xdg_util.h"
 
+#if defined(OS_FREEBSD)
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#endif
+
 namespace base {
 
 #if defined(OS_LINUX)
 const char kSelfExe[] = "/proc/self/exe";
 #elif defined(OS_SOLARIS)
 const char kSelfExe[] = getexecname();
 #endif
 
 // The name of this file relative to the source root. This is used for checking
 // that the source checkout is in the correct place.
@@ skipping 75 matching lines @@
       scoped_ptr<base::Environment> env(base::Environment::Create());
       FilePath cache_dir(base::nix::GetXDGDirectory(env.get(), "XDG_CACHE_HOME",
                                                     ".cache"));
       *result = cache_dir;
       return true;
   }
   return false;
 }
 
 }  // namespace base