cros: Enable WebUILoginView reuse.

components/proximity_auth/screenlock_bridge.cc

 // Copyright 2014 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 "components/proximity_auth/screenlock_bridge.h"
 
 #include "base/strings/string16.h"
 #include "build/build_config.h"
 #include "components/proximity_auth/logging/logging.h"
 
@@ skipping 99 matching lines @@
 void ScreenlockBridge::UserPodCustomIconOptions::SetTrialRun() {
   is_trial_run_ = true;
 }
 
 // static
 ScreenlockBridge* ScreenlockBridge::Get() {
   return g_screenlock_bridge_instance.Pointer();
 }
 
 void ScreenlockBridge::SetLockHandler(LockHandler* lock_handler) {
-  DCHECK(lock_handler_ == nullptr || lock_handler == nullptr);
-
   // Don't notify observers if there is no change -- i.e. if the screen was
   // already unlocked, and is remaining unlocked.
   if (lock_handler == lock_handler_)
     return;
 
+  DCHECK(lock_handler_ == nullptr || lock_handler == nullptr);
+
   // TODO(isherman): If |lock_handler| is null, then |lock_handler_| might have
   // been freed. Cache the screen type rather than querying it below.
   LockHandler::ScreenType screen_type;
   if (lock_handler_)
     screen_type = lock_handler_->GetScreenType();
   else
     screen_type = lock_handler->GetScreenType();
 
   focused_account_id_ = EmptyAccountId();
   lock_handler_ = lock_handler;
@@ skipping 42 matching lines @@
   observers_.RemoveObserver(observer);
 }
 
 ScreenlockBridge::ScreenlockBridge()
     : lock_handler_(nullptr), focused_account_id_(EmptyAccountId()) {}
 
 ScreenlockBridge::~ScreenlockBridge() {
 }
 
 }  // namespace proximity_auth