posix: refactor duplicated path-handling code

We had the same code in three headers, and an "if FREEBSD" in a
_linux.cc file.

Review URL: http://codereview.chromium.org/414063

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@32722 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/base/base_paths_mac.h b/base/base_paths_mac.h
index 324fc6c8..60dd0f3 100644
--- a/base/base_paths_mac.h
+++ b/base/base_paths_mac.h
@@ -14,15 +14,9 @@
 enum {
   PATH_MAC_START = 200,
 
-  FILE_EXE,     // path and filename of the current executable
-  FILE_MODULE,  // path and filename of the module containing the code for the
-                // PathService (which could differ from FILE_EXE if the
-                // PathService were compiled into a library, for example)
   DIR_CACHE,    // ~/Library/Caches
   DIR_APP_DATA,  // ~/Library/Application Support
-  DIR_SOURCE_ROOT,  // Returns the root of the source tree.  This key is useful
-                    // for tests that need to locate various resources.  It
-                    // should not be used outside of test code.
+
   PATH_MAC_END
 };