chrome_paths: refactor and sanitize cache directory handling

base/base_paths_linux.cc

Index: base/base_paths_linux.cc
diff --git a/base/base_paths_linux.cc b/base/base_paths_linux.cc
index 6d837f293ac605b21a3144b5965622a34da46da2..53076f7f16361ed9fc60977eac0fd021af0c4fe6 100644
--- a/base/base_paths_linux.cc
+++ b/base/base_paths_linux.cc
@@ -105,12 +105,6 @@ bool PathProviderPosix(int key, FilePath* result) {
                  << "Try running from your chromium/src directory.";
       return false;
     }
-    case base::DIR_USER_CACHE:
-      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;
 }