Remove last usage functions from HostContentSettingsMap and clean up prefs

chrome/browser/permissions/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 "chrome/browser/permissions/permission_manager.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/callback.h"
@@ skipping 406 matching lines @@
     PermissionType permission,
     const GURL& requesting_origin,
     const GURL& embedding_origin) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   if (IsConstantPermission(permission))
     return GetPermissionStatusForConstantPermission(permission);
   return GetPermissionStatus(PermissionTypeToContentSetting(permission),
                              requesting_origin, embedding_origin);
 }
 
-void PermissionManager::RegisterPermissionUsage(PermissionType permission,
-                                                const GURL& requesting_origin,
-                                                const GURL& embedding_origin) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  // This is required because constant permissions don't have a
-  // ContentSettingsType.
-  if (IsConstantPermission(permission))
-    return;
-
-  HostContentSettingsMapFactory::GetForProfile(profile_)->UpdateLastUsage(
-      requesting_origin,
-      embedding_origin,
-      PermissionTypeToContentSetting(permission));
-}
-
 int PermissionManager::SubscribePermissionStatusChange(
     PermissionType permission,
     const GURL& requesting_origin,
     const GURL& embedding_origin,
     const base::Callback<void(PermissionStatus)>& callback) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   if (subscriptions_.IsEmpty())
     HostContentSettingsMapFactory::GetForProfile(profile_)->AddObserver(this);
 
   auto subscription = base::MakeUnique<Subscription>();
@@ skipping 58 matching lines @@
     subscription->current_value = new_value;
 
     // Add the callback to |callbacks| which will be run after the loop to
     // prevent re-entrance issues.
     callbacks.push_back(base::Bind(subscription->callback, new_value));
   }
 
   for (const auto& callback : callbacks)
     callback.Run();
 }