Notify inspector of stylesheet changes when removing tree scopes.

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

 /*
  * 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, 2010, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 249 matching lines @@
   DECLARE_VIRTUAL_TRACE();
   DECLARE_TRACE_WRAPPERS();
 
  private:
   // CSSFontSelectorClient implementation.
   void fontsNeedUpdate(CSSFontSelector*) override;
 
  private:
   StyleEngine(Document&);
   bool needsActiveStyleSheetUpdate() const {
-    return m_allTreeScopesDirty || m_documentScopeDirty ||
-           m_dirtyTreeScopes.size();
+    return m_allTreeScopesDirty || m_treeScopesRemoved ||
+           m_documentScopeDirty || m_dirtyTreeScopes.size();
   }
 
   TreeScopeStyleSheetCollection* ensureStyleSheetCollectionFor(TreeScope&);
   TreeScopeStyleSheetCollection* styleSheetCollectionFor(TreeScope&);
   bool shouldUpdateDocumentStyleSheetCollection() const;
   bool shouldUpdateShadowTreeStyleSheetCollection() const;
 
   void markDocumentDirty();
   void markTreeScopeDirty(TreeScope&);
 
@@ skipping 64 matching lines @@
 
   Member<StyleRuleUsageTracker> m_tracker;
 
   using StyleSheetCollectionMap =
       HeapHashMap<WeakMember<TreeScope>,
                   Member<ShadowTreeStyleSheetCollection>>;
   StyleSheetCollectionMap m_styleSheetCollectionMap;
 
   bool m_documentScopeDirty = true;
   bool m_allTreeScopesDirty = false;
+  bool m_treeScopesRemoved = false;
   UnorderedTreeScopeSet m_dirtyTreeScopes;
   UnorderedTreeScopeSet m_activeTreeScopes;
   DocumentOrderedList m_treeBoundaryCrossingScopes;
 
   String m_preferredStylesheetSetName;
   String m_selectedStylesheetSetName;
 
   CSSGlobalRuleSet m_globalRuleSet;
 
   bool m_usesRemUnits = false;
@@ skipping 11 matching lines @@
 
   std::unique_ptr<StyleResolverStats> m_styleResolverStats;
   unsigned m_styleForElementCount = 0;
 
   friend class StyleEngineTest;
 };
 
 }  // namespace blink
 
 #endif