Correct the activation of idle time spell checker on document attach

third_party/WebKit/Source/core/editing/spellcheck/IdleSpellCheckCallback.cpp

 // Copyright 2016 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 "core/editing/spellcheck/IdleSpellCheckCallback.h"
 
 #include "core/dom/IdleRequestOptions.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/Editor.h"
@@ skipping 228 matching lines @@
 bool IdleSpellCheckCallback::coldModeFinishesFullDocument() const {
   if (m_needsMoreColdModeInvocationForTesting) {
     m_needsMoreColdModeInvocationForTesting = false;
     return false;
   }
 
   return !m_nextNodeInColdMode;
 }
 
 void IdleSpellCheckCallback::handleEvent(IdleDeadline* deadline) {
+  DCHECK(RuntimeEnabledFeatures::idleTimeSpellCheckingEnabled());
   DCHECK(frame().document());
   DCHECK(frame().document()->isActive());
   DCHECK_NE(m_idleCallbackHandle, kInvalidHandle);
   m_idleCallbackHandle = kInvalidHandle;
 
   if (!isSpellCheckingEnabled()) {
     deactivate();
     return;
   }
 
@@ skipping 49 matching lines @@
   }
 }
 
 void IdleSpellCheckCallback::skipColdModeTimerForTesting() {
   DCHECK(m_coldModeTimer.isActive());
   m_coldModeTimer.stop();
   coldModeTimerFired(&m_coldModeTimer);
 }
 
 }  // namespace blink