[PAUSED] Add a scope for disallowing style update when calling hasEditableStyle

third_party/WebKit/Source/core/dom/DocumentLifecycle.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 132 matching lines @@
         : m_documentLifecycle(documentLifecycle) {
       m_documentLifecycle.incrementDetachCount();
     }
 
     ~DetachScope() { m_documentLifecycle.decrementDetachCount(); }
 
    private:
     DocumentLifecycle& m_documentLifecycle;
   };
 
+  // This scope should only be used when we need to call hasEditableStyle(), but
+  // the document's style may be dirty and cannot be updated due to some other
+  // blockers. In the long term, we should fix those blockers and remove this
+  // scope.  See crbug.com/667575 for details.
+  class DisallowStyleRecalcScope {
+    STACK_ALLOCATED();
+    WTF_MAKE_NONCOPYABLE(DisallowStyleRecalcScope);

[yosin_UTC9, 2016/11/25 09:52:37]

Use |DISALLOW_COPY_AND_ASSIGN(DisallowStyleRecalcScope)|

[Xiaocheng, 2016/11/25 10:05:32]

Done.

+
+   public:
+    explicit DisallowStyleRecalcScope(DocumentLifecycle& documentLifecycle)
+        : m_documentLifecycle(documentLifecycle) {
+      m_documentLifecycle.incrementNoStyleRecalcCount();
+    }
+
+    ~DisallowStyleRecalcScope() {
+      m_documentLifecycle.decrementNoStyleRecalcCount();
+    }
+
+   private:
+    DocumentLifecycle& m_documentLifecycle;
+  };
+
   // Throttling is disabled by default. Instantiating this class allows
   // throttling (e.g., during BeginMainFrame). If a script needs to run inside
   // this scope, DisallowThrottlingScope should be used to let the script
   // perform a synchronous layout if necessary.
   class CORE_EXPORT AllowThrottlingScope {
     STACK_ALLOCATED();
     WTF_MAKE_NONCOPYABLE(AllowThrottlingScope);
 
    public:
     AllowThrottlingScope(DocumentLifecycle&);
@@ skipping 34 matching lines @@
     m_disallowTransitionCount--;
   }
 
   bool inDetach() const { return m_detachCount; }
   void incrementDetachCount() { m_detachCount++; }
   void decrementDetachCount() {
     DCHECK_GT(m_detachCount, 0);
     m_detachCount--;
   }
 
+  bool styleRecalcDisallowed() const { return m_disallowStyleRecalcCount; }
+  void incrementNoStyleRecalcCount() { ++m_disallowStyleRecalcCount; }
+  void decrementNoStyleRecalcCount() { --m_disallowStyleRecalcCount; }
+
   bool throttlingAllowed() const;
 
  private:
 #if DCHECK_IS_ON()
   static const char* stateAsDebugString(const LifecycleState);
   bool canAdvanceTo(LifecycleState) const;
   bool canRewindTo(LifecycleState) const;
 #endif
 
   LifecycleState m_state;
   int m_detachCount;
   int m_disallowTransitionCount;
+  int m_disallowStyleRecalcCount;
 };
 
 inline bool DocumentLifecycle::stateAllowsTreeMutations() const {
   // FIXME: We should not allow mutations in InPreLayout or AfterPerformLayout
   // either, but we need to fix MediaList listeners and plugins first.
   return m_state != InStyleRecalc && m_state != InPerformLayout &&
          m_state != InCompositingUpdate && m_state != InPrePaint &&
          m_state != InPaint;
 }
 
@@ skipping 17 matching lines @@
 
 inline bool DocumentLifecycle::stateAllowsLayoutInvalidation() const {
   return m_state != InPerformLayout && m_state != InCompositingUpdate &&
          m_state != InPaintInvalidation && m_state != InPrePaint &&
          m_state != InPaint;
 }
 
 }  // namespace blink
 
 #endif