Remove last usage functions from HostContentSettingsMap and clean up prefs

content/shell/browser/layout_test/layout_test_permission_manager.cc

 // Copyright 2015 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 "content/shell/browser/layout_test/layout_test_permission_manager.h"
 
 #include <list>
 #include <memory>
 #include <utility>
 
@@ skipping 117 matching lines @@
 
   base::AutoLock lock(permissions_lock_);
 
   auto it = permissions_.find(
       PermissionDescription(permission, requesting_origin, embedding_origin));
   if (it == permissions_.end())
     return blink::mojom::PermissionStatus::DENIED;
   return it->second;
 }
 
-void LayoutTestPermissionManager::RegisterPermissionUsage(
-    PermissionType permission,
-    const GURL& requesting_origin,
-    const GURL& embedding_origin) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-}
-
 int LayoutTestPermissionManager::SubscribePermissionStatusChange(
     PermissionType permission,
     const GURL& requesting_origin,
     const GURL& embedding_origin,
     const base::Callback<void(blink::mojom::PermissionStatus)>& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   auto subscription = base::MakeUnique<Subscription>();
   subscription->permission =
       PermissionDescription(permission, requesting_origin, embedding_origin);
@@ skipping 63 matching lines @@
     // Add the callback to |callbacks| which will be run after the loop to
     // prevent re-entrance issues.
     callbacks.push_back(base::Bind(subscription->callback, status));
   }
 
   for (const auto& callback : callbacks)
     callback.Run();
 }
 
 }  // namespace content