Refactor setImportsController() to clarify invariants

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 886 matching lines @@
   return constructorBuilder.bindingsReturnValue();
 }
 
 V0CustomElementMicrotaskRunQueue* Document::customElementMicrotaskRunQueue() {
   if (!m_customElementMicrotaskRunQueue)
     m_customElementMicrotaskRunQueue =
         V0CustomElementMicrotaskRunQueue::create();
   return m_customElementMicrotaskRunQueue.get();
 }
 
-void Document::setImportsController(HTMLImportsController* controller) {
-  DCHECK(!m_importsController || !controller);
-  m_importsController = controller;
-  if (!m_importsController && !loader())
+void Document::clearImportsController() {
+  m_importsController = nullptr;
+  if (!loader())
     m_fetcher->clearContext();
 }
 
+void Document::createImportsController() {
+  DCHECK(!m_importsController);
+  m_importsController = HTMLImportsController::create(*this);
+}
+
 HTMLImportLoader* Document::importLoader() const {
   if (!m_importsController)
     return 0;
   return m_importsController->loaderFor(*this);
 }
 
 bool Document::haveImportsLoaded() const {
   if (!m_importsController)
     return true;
   return !m_importsController->shouldBlockScriptExecution(*this);
@@ skipping 1549 matching lines @@
   // to the DocumentLoader when possible also prevents prematurely clearing
   // the context in the case where multiple Documents end up associated with
   // a single DocumentLoader (e.g., navigating to a javascript: url).
   if (!loader())
     m_fetcher->clearContext();
   // If this document is the master for an HTMLImportsController, sever that
   // relationship. This ensures that we don't leave import loads in flight,
   // thinking they should have access to a valid frame when they don't.
   if (m_importsController) {
     m_importsController->dispose();
-    setImportsController(nullptr);
+    clearImportsController();
   }
 
   m_timers.setTimerTaskRunner(Platform::current()
                                   ->currentThread()
                                   ->scheduler()
                                   ->timerTaskRunner()
                                   ->clone());
 
   if (m_mediaQueryMatcher)
     m_mediaQueryMatcher->documentDetached();
@@ skipping 4077 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->url().getString().utf8().data());
 }
 #endif