Fixed perf regression by removing tree traversal for text sibling.

third_party/WebKit/Source/core/dom/Document.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 23 matching lines @@
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/TraceWrapperMember.h"
 #include "core/CoreExport.h"
 #include "core/dom/ContainerNode.h"
 #include "core/dom/DocumentEncodingData.h"
 #include "core/dom/DocumentInit.h"
 #include "core/dom/DocumentLifecycle.h"
 #include "core/dom/DocumentTiming.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/dom/MutationObserver.h"
+#include "core/dom/Text.h"
 #include "core/dom/TextLinkColors.h"
 #include "core/dom/TreeScope.h"
 #include "core/dom/UserActionElementSet.h"
 #include "core/dom/ViewportDescription.h"
 #include "core/dom/custom/V0CustomElement.h"
 #include "core/fetch/ClientHintsPreferences.h"
 #include "core/frame/DOMTimerCoordinator.h"
 #include "core/frame/HostsUsingFeatures.h"
 #include "core/html/parser/ParserSynchronizationPolicy.h"
 #include "core/page/PageVisibilityState.h"
+#include "core/style/ComputedStyle.h"
 #include "platform/Length.h"
 #include "platform/Timer.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/ReferrerPolicy.h"
 #include "public/platform/WebFocusType.h"
 #include "public/platform/WebInsecureRequestPolicy.h"
 #include "wtf/HashSet.h"
 #include "wtf/PassRefPtr.h"
 #include <memory>
 
@@ skipping 88 matching lines @@
 class SecurityOrigin;
 class SegmentedString;
 class SelectorQueryCache;
 class SerializedScriptValue;
 class Settings;
 class SnapCoordinator;
 class StringOrDictionary;
 class StyleEngine;
 class StyleResolver;
 class StyleSheetList;
-class Text;
 class TextAutosizer;
 class Touch;
 class TouchList;
 class TransformSource;
 class TreeWalker;
 class VisitedLinkState;
 enum class SelectionBehaviorOnFocus;
 struct AnnotatedRegionValue;
 struct FocusParams;
 struct IconURL;
@@ skipping 71 matching lines @@
   WouldLoadZeroByZero,
   WouldLoadAboveAndLeft,
   WouldLoadAbove,
   WouldLoadLeft,
   // We have to load documents in visible frames.
   WouldLoadVisible,
 
   WouldLoadReasonEnd
 };
 
+struct StyleRecalcData : public GarbageCollectedFinalized<StyleRecalcData> {

[rune, 2016/11/07 09:43:19]

This is only used for reattachment, right? How about calling it
StyleReattachData or smth. I was worried we store these objects for all elements
being recalc'ed when I first saw it.

Could we perhaps put this class in a separate include file and just forward
declare it in Document.h?

+  StyleRecalcData(RefPtr<ComputedStyle> computedStyle, Text* nextTextSibling)
+      : computedStyle(std::move(computedStyle)),
+        nextTextSibling(nextTextSibling) {}
+
+  RefPtr<ComputedStyle> computedStyle;
+  Member<Text> nextTextSibling;
+
+  DEFINE_INLINE_TRACE() { visitor->trace(nextTextSibling); }
+};
+
 using DocumentClassFlags = unsigned char;
 
 class CORE_EXPORT Document : public ContainerNode,
                              public TreeScope,
                              public SecurityContext,
                              public ExecutionContext,
                              public Supplementable<Document> {
   DEFINE_WRAPPERTYPEINFO();
   USING_GARBAGE_COLLECTED_MIXIN(Document);
 
@@ skipping 74 matching lines @@
   Element* createElementNS(const AtomicString& namespaceURI,
                            const AtomicString& qualifiedName,
                            ExceptionState&);
   Element* createElement(const QualifiedName&, CreateElementFlags);
 
   Element* elementFromPoint(int x, int y) const;
   HeapVector<Member<Element>> elementsFromPoint(int x, int y) const;
   Range* caretRangeFromPoint(int x, int y);
   Element* scrollingElement();
 
-  void addNonAttachedStyle(Element&, RefPtr<ComputedStyle>);
-  ComputedStyle* getNonAttachedStyle(Element&);
+  void addStyleRecalcData(Element&, StyleRecalcData*);
+  StyleRecalcData* getStyleRecalcData(Element&);
 
   String readyState() const;
 
   AtomicString characterSet() const { return Document::encodingName(); }
 
   AtomicString encodingName() const;
 
   void setContent(const String&);
 
   String suggestedMIMEType() const;
@@ skipping 1083 matching lines @@
   PendingSheetLayout m_pendingSheetLayout;
 
   Member<LocalFrame> m_frame;
   Member<LocalDOMWindow> m_domWindow;
   TraceWrapperMember<HTMLImportsController> m_importsController;
 
   Member<ResourceFetcher> m_fetcher;
   Member<DocumentParser> m_parser;
   Member<ContextFeatures> m_contextFeatures;
 
-  HeapHashMap<Member<Element>, RefPtr<ComputedStyle>> m_nonAttachedStyle;
+  HeapHashMap<Member<Element>, Member<StyleRecalcData>> m_styleRecalcDataMap;

[esprehn, 2016/11/07 22:26:26]

HeapHashMap<Member<Element>, StyleRecalcData>

that way we avoid tons of heap allocations. That produces some waste inside the
map, but it's okay since this is just temporary inside updateStyle.

 
   bool m_wellFormed;
 
   // Document URLs.
   KURL m_url;  // Document.URL: The URL from which this document was retrieved.
   KURL m_baseURL;  // Node.baseURI: The URL to use when resolving relative URLs.
   KURL m_baseURLOverride;  // An alternative base URL that takes precedence over
                            // m_baseURL (but not m_baseElementURL).
   KURL m_baseElementURL;   // The URL set by the <base> element.
   KURL m_cookieURL;        // The URL to use for cookie access.
@@ skipping 259 matching lines @@
 DEFINE_TYPE_CASTS(TreeScope, Document, document, true, true);
 
 }  // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 CORE_EXPORT void showLiveDocumentInstances();
 #endif
 
 #endif  // Document_h