Move some XDG code from chrome to base.

base/linux_util.h

 // Copyright (c) 2009 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.
 
 #ifndef BASE_LINUX_UTIL_H__
 #define BASE_LINUX_UTIL_H__
 
 #include <stdint.h>
 #include <sys/types.h>
 
 #include <string>
 
+class FilePath;
+
 namespace base {
 
 static const char kFindInodeSwitch[] = "--find-inode";
 
 // Makes a copy of |pixels| with the ordering changed from BGRA to RGBA.
 // The caller is responsible for free()ing the data. If |stride| is 0,
 // it's assumed to be 4 * |width|.
 uint8_t* BGRAToRGBA(const uint8_t* pixels, int width, int height, int stride);
 
 // Get the Linux Distro if we can, or return "Unknown", similar to
 // GetWinVersion() in base/win_util.h.
 std::string GetLinuxDistro();
 
 // These are used to derive mocks for unittests.
 class EnvironmentVariableGetter {
  public:
   virtual ~EnvironmentVariableGetter() {}
   // Gets an environment variable's value and stores it in
   // result. Returns false if the key is unset.
   virtual bool Getenv(const char* variable_name, std::string* result) = 0;
 
   // Create an instance of EnvironmentVariableGetter
   static EnvironmentVariableGetter* Create();
 };
 
+// Get the home directory.
+FilePath GetHomeDir(EnvironmentVariableGetter* env);
+
+// Utility function for getting XDG directories.
+// |env_name| is the name of an environment variable that we want to use to get
+// a directory path. |fallback_dir| is the directory relative to $HOME that we
+// use if |env_name| cannot be found or is empty. |fallback_dir| may be NULL.
+// Examples of |env_name| are XDG_CONFIG_HOME and XDG_DATA_HOME.
+FilePath GetXDGDirectory(EnvironmentVariableGetter* env,
+                         const char* env_name, const char* fallback_dir);
+
+// Wrapper around xdg_user_dir_lookup() from src/base/third_party/xdg-user-dirs
+// This looks up "well known" user directories like the desktop and music
+// folder. Examples of |dir_name| are DESKTOP and MUSIC.
+FilePath GetXDGUserDirectory(EnvironmentVariableGetter* env,
+                             const char* dir_name, const char* fallback_dir);
+
 enum DesktopEnvironment {
   DESKTOP_ENVIRONMENT_OTHER,
   DESKTOP_ENVIRONMENT_GNOME,
   // KDE3 and KDE4 are sufficiently different that we count
   // them as two different desktop environments here.
   DESKTOP_ENVIRONMENT_KDE3,
   DESKTOP_ENVIRONMENT_KDE4,
 };
 
 // Return an entry from the DesktopEnvironment enum with a best guess
@@ skipping 11 matching lines @@
 // Return the inode number for the UNIX domain socket |fd|.
 bool FileDescriptorGetInode(ino_t* inode_out, int fd);
 
 // Find the process which holds the given socket, named by inode number. If
 // multiple processes hold the socket, this function returns false.
 bool FindProcessHoldingSocket(pid_t* pid_out, ino_t socket_inode);
 
 }  // namespace base
 
 #endif  // BASE_LINUX_UTIL_H__