ComponentCloudPolicyService tracks the signin state.

chrome/browser/policy/cloud/resource_cache.cc

 // Copyright (c) 2013 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 "chrome/browser/policy/cloud/resource_cache.h"
 
 #include "base/base64.h"
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/files/file_enumerator.h"
@@ skipping 119 matching lines @@
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   base::FilePath subkey_path;
   if (VerifyKeyPathAndGetSubkeyPath(key, false, subkey, &subkey_path))
     base::DeleteFile(subkey_path, false);
   // Delete() does nothing if the directory given to it is not empty. Hence, the
   // call below deletes the directory representing |key| if its last subkey was
   // just removed and does nothing otherwise.
   base::DeleteFile(subkey_path.DirName(), false);
 }
 
+void ResourceCache::Clear(const std::string& key) {
+  DCHECK(task_runner_->RunsTasksOnCurrentThread());
+  base::FilePath key_path;
+  if (VerifyKeyPath(key, false, &key_path))
+    base::DeleteFile(key_path, true);
+}
+
 void ResourceCache::FilterSubkeys(const std::string& key,
                                   const SubkeyFilter& test) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
   base::FilePath key_path;
   if (!VerifyKeyPath(key, false, &key_path))
     return;
 
   base::FileEnumerator enumerator(key_path, false, base::FileEnumerator::FILES);
   for (base::FilePath subkey_path = enumerator.Next();
@@ skipping 74 matching lines @@
   if (!VerifyKeyPath(key, allow_create_key, &key_path) ||
       !Base64Encode(subkey, &encoded)) {
     return false;
   }
   *path = key_path.AppendASCII(encoded);
   return true;
 }
 
 
 }  // namespace policy