Make functions in fileutils.h use "const std::string&".

webrtc/test/testsupport/fileutils.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 83 matching lines @@
 #ifdef WIN32
   std::replace(temp_path.begin(), temp_path.end(), '/', '\\');
 #endif
 
   // Trim away the executable name; only store the relative dir path.
   temp_path = temp_path.substr(0, temp_path.find_last_of(kPathDelimiter));
   strncpy(relative_dir_path, temp_path.c_str(), FILENAME_MAX);
   relative_dir_path_set = true;
 }
 
-bool FileExists(std::string& file_name) {
+bool FileExists(const std::string& file_name) {
   struct stat file_info = {0};
   return stat(file_name.c_str(), &file_info) == 0;
 }
 
 #ifdef WEBRTC_ANDROID
 
 std::string ProjectRootPath() {
   return kRootDirName;
 }
 
@@ skipping 84 matching lines @@
     assert(false);
     return "";
   } else {
     ::close(fd);
   }
   std::string ret(tempname.get());
   return ret;
 #endif
 }
 
-bool CreateDir(std::string directory_name) {
+bool CreateDir(const std::string& directory_name) {
   struct stat path_info = {0};
   // Check if the path exists already:
   if (stat(directory_name.c_str(), &path_info) == 0) {
     if (!S_ISDIR(path_info.st_mode)) {
       fprintf(stderr, "Path %s exists but is not a directory! Remove this "
               "file and re-run to create the directory.\n",
               directory_name.c_str());
       return false;
     }
   } else {
 #ifdef WIN32
     return _mkdir(directory_name.c_str()) == 0;
 #else
     return mkdir(directory_name.c_str(),  S_IRWXU | S_IRWXG | S_IRWXO) == 0;
 #endif
   }
   return true;
 }
 
-std::string ResourcePath(std::string name, std::string extension) {
+std::string ResourcePath(const std::string& name,
+                         const std::string& extension) {
 #if defined(WEBRTC_IOS)
   return IOSResourcePath(name, extension);
 #else
   std::string platform = "win";
 #ifdef WEBRTC_LINUX
   platform = "linux";
 #endif  // WEBRTC_LINUX
 #ifdef WEBRTC_MAC
   platform = "mac";
 #endif  // WEBRTC_MAC
@@ skipping 23 matching lines @@
   resource_file = resources_path + name + "_" + architecture + "." + extension;
   if (FileExists(resource_file)) {
     return resource_file;
   }
 
   // Fall back on name without architecture or platform.
   return resources_path + name + "." + extension;
 #endif  // defined (WEBRTC_IOS)
 }
 
-size_t GetFileSize(std::string filename) {
+size_t GetFileSize(const std::string& filename) {
   FILE* f = fopen(filename.c_str(), "rb");
   size_t size = 0;
   if (f != NULL) {
     if (fseek(f, 0, SEEK_END) == 0) {
       size = ftell(f);
     }
     fclose(f);
   }
   return size;
 }
 
 }  // namespace test
 }  // namespace webrtc