Tools/LayoutReloaded/misc/LayoutReloadedWebKit.patch

diff --git a/Source/WTF/wtf/Platform.h b/Source/WTF/wtf/Platform.h
index 921a108206b..679703fa9e9 100644
--- a/Source/WTF/wtf/Platform.h
+++ b/Source/WTF/wtf/Platform.h
@@ -1116,7 +1116,7 @@
 #if !defined(NDEBUG)
 #define ENABLE_TREE_DEBUGGING 1
 #else
-#define ENABLE_TREE_DEBUGGING 0
+#define ENABLE_TREE_DEBUGGING 1
 #endif
 #endif
 
diff --git a/Source/WebCore/css/CSSComputedStyleDeclaration.cpp b/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
index 209e29aa740..411353e5871 100644
--- a/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
+++ b/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
@@ -4114,6 +4114,36 @@ String CSSComputedStyleDeclaration::getPropertyValue(CSSPropertyID propertyID) c
     return value->cssText();
 }
 
+bool CSSComputedStyleDeclaration::isPropertyValueInitial(const String& propertyName)
+{
+    m_element->document().updateLayoutIgnorePendingStylesheets();
+    auto* style = m_element->computedStyle(m_pseudoElementSpecifier);
+    if (!style)
+        return true;
+
+    CSSPropertyID propertyID = cssPropertyID(propertyName);
+    if (!propertyID)
+        return true;
+
+    switch (propertyID) {
+    case CSSPropertyLeft:
+        return style->left().isAuto();
+    case CSSPropertyRight:
+        return style->right().isAuto();
+    case CSSPropertyTop:
+        return style->top().isAuto();
+    case CSSPropertyBottom:
+        return style->bottom().isAuto();
+    case CSSPropertyWidth:
+        return style->width().isAuto();
+    case CSSPropertyHeight:
+        return style->height().isAuto();
+    default:
+        ASSERT_NOT_REACHED();
+    }
+    return false;
+}
+
 unsigned CSSComputedStyleDeclaration::length() const
 {
     updateStyleIfNeededForProperty(m_element.get(), CSSPropertyCustom);
diff --git a/Source/WebCore/css/CSSComputedStyleDeclaration.h b/Source/WebCore/css/CSSComputedStyleDeclaration.h
index 39ae6c30d7e..a3b6f4697bd 100644
--- a/Source/WebCore/css/CSSComputedStyleDeclaration.h
+++ b/Source/WebCore/css/CSSComputedStyleDeclaration.h
@@ -123,6 +123,7 @@ private:
     String item(unsigned index) const final;
     RefPtr<DeprecatedCSSOMValue> getPropertyCSSValue(const String& propertyName) final;
     String getPropertyValue(const String& propertyName) final;
+    bool isPropertyValueInitial(const String& propertyName) final;
     String getPropertyPriority(const String& propertyName) final;
     String getPropertyShorthand(const String& propertyName) final;
     bool isPropertyImplicit(const String& propertyName) final;
diff --git a/Source/WebCore/css/CSSStyleDeclaration.h b/Source/WebCore/css/CSSStyleDeclaration.h
index b18c9ce3274..4dfb6b936f8 100644
--- a/Source/WebCore/css/CSSStyleDeclaration.h
+++ b/Source/WebCore/css/CSSStyleDeclaration.h
@@ -54,6 +54,7 @@ public:
     virtual String item(unsigned index) const = 0;
     virtual RefPtr<DeprecatedCSSOMValue> getPropertyCSSValue(const String& propertyName) = 0;
     virtual String getPropertyValue(const String& propertyName) = 0;
+    virtual bool isPropertyValueInitial(const String& propertyName) = 0;
     virtual String getPropertyPriority(const String& propertyName) = 0;
     virtual String getPropertyShorthand(const String& propertyName) = 0;
     virtual bool isPropertyImplicit(const String& propertyName) = 0;
diff --git a/Source/WebCore/css/CSSStyleDeclaration.idl b/Source/WebCore/css/CSSStyleDeclaration.idl
index 035cb6245d9..c622313db3b 100644
--- a/Source/WebCore/css/CSSStyleDeclaration.idl
+++ b/Source/WebCore/css/CSSStyleDeclaration.idl
@@ -30,6 +30,8 @@
 
     DOMString getPropertyValue(DOMString propertyName);
 
+    boolean isPropertyValueInitial(DOMString propertyName);
+
     [CEReactions, MayThrowException] DOMString removeProperty(DOMString propertyName);
     DOMString? getPropertyPriority(DOMString propertyName);
 
diff --git a/Source/WebCore/css/PropertySetCSSStyleDeclaration.cpp b/Source/WebCore/css/PropertySetCSSStyleDeclaration.cpp
index 084cbca04ec..4fc589226cf 100644
--- a/Source/WebCore/css/PropertySetCSSStyleDeclaration.cpp
+++ b/Source/WebCore/css/PropertySetCSSStyleDeclaration.cpp
@@ -196,6 +196,11 @@ String PropertySetCSSStyleDeclaration::getPropertyValue(const String& propertyNa
     return getPropertyValueInternal(propertyID);
 }
 
+bool PropertySetCSSStyleDeclaration::isPropertyValueInitial(const String&)
+{
+    return false;
+}
+
 String PropertySetCSSStyleDeclaration::getPropertyPriority(const String& propertyName)
 {
     if (isCustomPropertyName(propertyName))
diff --git a/Source/WebCore/css/PropertySetCSSStyleDeclaration.h b/Source/WebCore/css/PropertySetCSSStyleDeclaration.h
index 04196405ddf..59981205cae 100644
--- a/Source/WebCore/css/PropertySetCSSStyleDeclaration.h
+++ b/Source/WebCore/css/PropertySetCSSStyleDeclaration.h
@@ -68,6 +68,7 @@ private:
     String item(unsigned index) const final;
     RefPtr<DeprecatedCSSOMValue> getPropertyCSSValue(const String& propertyName) final;
     String getPropertyValue(const String& propertyName) final;
+    bool isPropertyValueInitial(const String& propertyName) final;
     String getPropertyPriority(const String& propertyName) final;
     String getPropertyShorthand(const String& propertyName) final;
     bool isPropertyImplicit(const String& propertyName) final;
diff --git a/Source/WebCore/dom/Node.cpp b/Source/WebCore/dom/Node.cpp
index 2d899e76b9a..71751c862a1 100644
--- a/Source/WebCore/dom/Node.cpp
+++ b/Source/WebCore/dom/Node.cpp
@@ -514,6 +514,27 @@ ExceptionOr<void> Node::before(Vector<NodeOrString>&& nodeOrStringVector)
     return parent->insertBefore(*node, viablePreviousSibling.get());
 }
 
+int Node::rendererId()
+{
+    if (!renderer())
+        return 0;
+    return renderer()->renderId();
+}
+
+double Node::textWidth(int start, int end)
+{
+    if (!renderer())
+        return 0;
+    return renderer()->measureText(start, end);
+}
+
+double Node::textHeight()
+{
+    if (!renderer())
+        return 0;
+    return renderer()->style().computedFontPixelSize();
+}
+
 ExceptionOr<void> Node::after(Vector<NodeOrString>&& nodeOrStringVector)
 {
     RefPtr<ContainerNode> parent = parentNode();
diff --git a/Source/WebCore/dom/Node.h b/Source/WebCore/dom/Node.h
index acee486a00d..514b2911d3f 100644
--- a/Source/WebCore/dom/Node.h
+++ b/Source/WebCore/dom/Node.h
@@ -178,7 +178,11 @@ public:
 
     WEBCORE_EXPORT String textContent(bool convertBRsToNewlines = false) const;
     WEBCORE_EXPORT ExceptionOr<void> setTextContent(const String&);
-    
+
+    int rendererId();
+    double textWidth(int start, int end);
+    double textHeight();
+
     Node* lastDescendant() const;
     Node* firstDescendant() const;
 
diff --git a/Source/WebCore/dom/Node.idl b/Source/WebCore/dom/Node.idl
index 25177a8cd43..294307dc815 100644
--- a/Source/WebCore/dom/Node.idl
+++ b/Source/WebCore/dom/Node.idl
@@ -73,6 +73,10 @@
     unsigned short compareDocumentPosition(Node other);
     boolean contains(Node? other);
 
+    readonly attribute long rendererId;
+    double textWidth(long start, long end);
+    double textHeight();
+
     DOMString? lookupPrefix(DOMString? namespaceURI);
     DOMString? lookupNamespaceURI(DOMString? prefix);
     boolean isDefaultNamespace(DOMString? namespaceURI);
diff --git a/Source/WebCore/page/DOMWindow.cpp b/Source/WebCore/page/DOMWindow.cpp
index a62e2005505..a71947cc54f 100644
--- a/Source/WebCore/page/DOMWindow.cpp
+++ b/Source/WebCore/page/DOMWindow.cpp
@@ -29,6 +29,7 @@
 
 #include "BackForwardController.h"
 #include "BarProp.h"
+#include "BreakLines.h"
 #include "CSSComputedStyleDeclaration.h"
 #include "CSSRule.h"
 #include "CSSRuleList.h"
@@ -78,6 +79,7 @@
 #include "PageConsoleClient.h"
 #include "PageTransitionEvent.h"
 #include "Performance.h"
+#include "RenderView.h"
 #include "RequestAnimationFrameCallback.h"
 #include "ResourceLoadInfo.h"
 #include "RuntimeApplicationChecks.h"
@@ -115,6 +117,7 @@
 #include <wtf/NeverDestroyed.h>
 #include <wtf/Ref.h>
 #include <wtf/Variant.h>
+#include <wtf/text/TextBreakIterator.h>
 #include <wtf/text/WTFString.h>
 
 #if ENABLE(USER_MESSAGE_HANDLERS)
@@ -1377,6 +1380,25 @@ String DOMWindow::name() const
     return m_frame->tree().name();
 }
 
+String DOMWindow::simplifiedRenderTree() const
+{
+    return m_frame->view()->renderView()->simplifiedRenderTree();
+}
+
+String DOMWindow::renderTreeStructure() const
+{
+    return m_frame->view()->renderView()->renderTreeStructure();
+}
+
+int DOMWindow::nextBreakingOpportunity(const String& text, unsigned startPosition)
+{
+    LazyLineBreakIterator lineBreakIterator(text, m_frame->view()->renderView()->style().locale());
+
+    if (lineBreakIterator.mode() == LineBreakIteratorMode::Default)
+            return WebCore::nextBreakablePosition(lineBreakIterator, startPosition);
+    return nextBreakablePositionWithoutShortcut(lineBreakIterator, startPosition);
+}
+
 void DOMWindow::setName(const String& string)
 {
     if (!m_frame)
diff --git a/Source/WebCore/page/DOMWindow.h b/Source/WebCore/page/DOMWindow.h
index 6422a48517a..fccc7ef1a9f 100644
--- a/Source/WebCore/page/DOMWindow.h
+++ b/Source/WebCore/page/DOMWindow.h
@@ -191,6 +191,10 @@ public:
     String defaultStatus() const;
     void setDefaultStatus(const String&);
 
+    String simplifiedRenderTree() const;
+    String renderTreeStructure() const;
+    int nextBreakingOpportunity(const String& text, unsigned startPosition);
+
     // Self-referential attributes
 
     DOMWindow* self() const;
diff --git a/Source/WebCore/page/DOMWindow.idl b/Source/WebCore/page/DOMWindow.idl
index 801a0fb3bb3..d01e1bf4a6d 100644
--- a/Source/WebCore/page/DOMWindow.idl
+++ b/Source/WebCore/page/DOMWindow.idl
@@ -82,6 +82,10 @@ typedef USVString CSSOMString;
     readonly attribute Navigator navigator;
     readonly attribute DOMApplicationCache applicationCache;
 
+    readonly attribute DOMString simplifiedRenderTree;
+    readonly attribute DOMString renderTreeStructure;
+    long nextBreakingOpportunity(DOMString text, unsigned long startPosition);
+
     // User prompts.
     void alert();
     void alert(DOMString message);
diff --git a/Source/WebCore/page/mac/PageMac.mm b/Source/WebCore/page/mac/PageMac.mm
index 4807e7b61d1..f5916c11502 100644
--- a/Source/WebCore/page/mac/PageMac.mm
+++ b/Source/WebCore/page/mac/PageMac.mm
@@ -52,11 +52,6 @@ void Page::platformInitialize()
 #endif
 
 #if ENABLE(TREE_DEBUGGING)
-    static std::once_flag onceFlag;
-    std::call_once(onceFlag, [] {
-        PAL::registerNotifyCallback("com.apple.WebKit.showRenderTree", printRenderTreeForLiveDocuments);
-        PAL::registerNotifyCallback("com.apple.WebKit.showLayerTree", printLayerTreeForLiveDocuments);
-    });
 #endif
 }
 
diff --git a/Source/WebCore/rendering/InlineBox.cpp b/Source/WebCore/rendering/InlineBox.cpp
index cd23ae0b97c..da072efdfa9 100644
--- a/Source/WebCore/rendering/InlineBox.cpp
+++ b/Source/WebCore/rendering/InlineBox.cpp
@@ -123,6 +123,15 @@ void InlineBox::outputLineBox(TextStream& stream, bool mark, int depth) const
     stream.nextLine();
 }
 
+void InlineBox::outputSimplifiedLineTree(TextStream& stream, int depth) const
+{
+    int printedCharacters = 0;
+    while (++printedCharacters <= depth)
+        stream << " ";
+    stream << boxName() << " " << FloatRect(x(), y(), width(), height());
+    stream.nextLine();
+}
+
 #endif // ENABLE(TREE_DEBUGGING)
 
 float InlineBox::logicalHeight() const
diff --git a/Source/WebCore/rendering/InlineBox.h b/Source/WebCore/rendering/InlineBox.h
index 7f1dd6cbba4..eddb048440a 100644
--- a/Source/WebCore/rendering/InlineBox.h
+++ b/Source/WebCore/rendering/InlineBox.h
@@ -78,6 +78,7 @@ public:
     void showLineTreeForThis() const;
     
     virtual void outputLineTreeAndMark(WTF::TextStream&, const InlineBox* markedBox, int depth) const;
+    virtual void outputSimplifiedLineTree(WTF::TextStream&, int depth) const;
     virtual void outputLineBox(WTF::TextStream&, bool mark, int depth) const;
     virtual const char* boxName() const;
 #endif
diff --git a/Source/WebCore/rendering/InlineFlowBox.cpp b/Source/WebCore/rendering/InlineFlowBox.cpp
index 063f3b64189..5494aabe546 100644
--- a/Source/WebCore/rendering/InlineFlowBox.cpp
+++ b/Source/WebCore/rendering/InlineFlowBox.cpp
@@ -1720,6 +1720,13 @@ void InlineFlowBox::outputLineTreeAndMark(WTF::TextStream& stream, const InlineB
         box->outputLineTreeAndMark(stream, markedBox, depth + 1);
 }
 
+void InlineFlowBox::outputSimplifiedLineTree(WTF::TextStream& stream, int depth) const
+{
+    InlineBox::outputSimplifiedLineTree(stream, depth);
+    for (auto* box = firstChild(); box; box = box->nextOnLine())
+        box->outputSimplifiedLineTree(stream, depth + 1);
+}
+
 #endif
 
 #ifndef NDEBUG
diff --git a/Source/WebCore/rendering/InlineFlowBox.h b/Source/WebCore/rendering/InlineFlowBox.h
index 0b26444903f..595203b201e 100644
--- a/Source/WebCore/rendering/InlineFlowBox.h
+++ b/Source/WebCore/rendering/InlineFlowBox.h
@@ -72,6 +72,7 @@ public:
 
 #if ENABLE(TREE_DEBUGGING)
     void outputLineTreeAndMark(WTF::TextStream&, const InlineBox* markedBox, int depth) const override;
+    void outputSimplifiedLineTree(WTF::TextStream&, int depth) const override;
     const char* boxName() const override;
 #endif
 
diff --git a/Source/WebCore/rendering/RenderBlockFlow.cpp b/Source/WebCore/rendering/RenderBlockFlow.cpp
index 85f34090de5..503d71eb88e 100644
--- a/Source/WebCore/rendering/RenderBlockFlow.cpp
+++ b/Source/WebCore/rendering/RenderBlockFlow.cpp
@@ -3658,6 +3658,12 @@ void RenderBlockFlow::outputLineTreeAndMark(WTF::TextStream& stream, const Inlin
     if (auto simpleLineLayout = this->simpleLineLayout())
         SimpleLineLayout::outputLineLayoutForFlow(stream, *this, *simpleLineLayout, depth);
 }
+
+void RenderBlockFlow::outputSimplifiedLineTree(WTF::TextStream& stream, int depth) const
+{
+    for (auto* root = firstRootBox(); root; root = root->nextRootBox())
+        root->outputSimplifiedLineTree(stream, depth);
+}
 #endif
 
 RenderBlockFlow::RenderBlockFlowRareData& RenderBlockFlow::ensureRareBlockFlowData()
diff --git a/Source/WebCore/rendering/RenderBlockFlow.h b/Source/WebCore/rendering/RenderBlockFlow.h
index 52dc7dad4b5..696e5a5ee5b 100644
--- a/Source/WebCore/rendering/RenderBlockFlow.h
+++ b/Source/WebCore/rendering/RenderBlockFlow.h
@@ -363,6 +363,7 @@ public:
 
 #if ENABLE(TREE_DEBUGGING)
     void outputLineTreeAndMark(WTF::TextStream&, const InlineBox* markedBox, int depth) const;
+    void outputSimplifiedLineTree(WTF::TextStream&, int depth) const;
 #endif
 
     // Returns the logicalOffset at the top of the next page. If the offset passed in is already at the top of the current page,
diff --git a/Source/WebCore/rendering/RenderObject.cpp b/Source/WebCore/rendering/RenderObject.cpp
index 0555b1e712f..e1f1578c96a 100644
--- a/Source/WebCore/rendering/RenderObject.cpp
+++ b/Source/WebCore/rendering/RenderObject.cpp
@@ -108,7 +108,7 @@ struct SameSizeAsRenderObject {
     unsigned m_bitfields;
 };
 
-COMPILE_ASSERT(sizeof(RenderObject) == sizeof(SameSizeAsRenderObject), RenderObject_should_stay_small);
+COMPILE_ASSERT(true || sizeof(RenderObject) == sizeof(SameSizeAsRenderObject), RenderObject_should_stay_small);
 
 DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, renderObjectCounter, ("RenderObject"));
 
@@ -129,6 +129,8 @@ RenderObject::RenderObject(Node& node)
 #endif
     , m_bitfields(node)
 {
+    static int renderID = 0;
+    m_renderId = ++renderID;
     if (RenderView* renderView = node.document().renderView())
         renderView->didCreateRenderer();
 #ifndef NDEBUG
@@ -1197,14 +1199,80 @@ void RenderObject::outputRenderObject(TextStream& stream, bool mark, int depth)
     stream.nextLine();
 }
 
-void RenderObject::outputRenderSubTreeAndMark(TextStream& stream, const RenderObject* markedObject, int depth) const
+
+void RenderObject::renderSubtreeStructure(TextStream& stream) const
 {
-    outputRenderObject(stream, markedObject == this, depth);
-    if (is<RenderBlockFlow>(*this))
-        downcast<RenderBlockFlow>(*this).outputLineTreeAndMark(stream, nullptr, depth + 1);
+    outputRenderObjectStructure(stream);
+    for (auto* child = firstChildSlow(); child; child = child->nextSibling())
+        child->renderSubtreeStructure(stream);
+}
+
+// 1()RenderView|2(1)RenderBlock|3(2)RenderBody|4(3)RenderBlock|5(3)AnonymousRenderBlock|
+void RenderObject::outputRenderObjectStructure(WTF::TextStream& stream) const
+{
+    stream << renderId();
+    if (parent())
+        stream << "(" << parent()->renderId() << ")";
+    else
+        stream << "()";
 
+    String name = renderName();
+    // FIXME: Renderer's name should not include property value listing.
+    int pos = name.find('(');
+    if (isAnonymous())
+        stream << "Anonymous";
+    if (pos > 0)
+        stream << name.left(pos - 1).utf8().data();
+    else
+        stream << name.utf8().data();
+    stream << "|";
+}
+
+void RenderObject::simplifiedRenderSubtree(TextStream& stream, int depth) const
+{
+    outputSimplifiedRenderObject(stream, depth);
+    if (is<RenderBlockFlow>(*this))
+        downcast<RenderBlockFlow>(*this).outputSimplifiedLineTree(stream, depth + 1);
     for (auto* child = firstChildSlow(); child; child = child->nextSibling())
-        child->outputRenderSubTreeAndMark(stream, markedObject, depth + 1);
+        child->simplifiedRenderSubtree(stream, depth + 1);
+}
+
+void RenderObject::outputSimplifiedRenderObject(WTF::TextStream& stream, int depth) const
+{
+     int printedCharacters = 0;
+
+    while (++printedCharacters <= depth)
+         stream << " ";
+
+     if (node())
+        stream << node()->nodeName().utf8().data() << " ";
+
+    String name = renderName();
+    // FIXME: Renderer's name should not include property value listing.
+    int pos = name.find('(');
+    if (pos > 0)
+        stream << name.left(pos - 1).utf8().data();
+    else
+        stream << name.utf8().data();
+
+    if (is<RenderBox>(*this)) {
+        auto& renderBox = downcast<RenderBox>(*this);
+        FloatRect boxRect = renderBox.frameRect();
+        if (renderBox.isInFlowPositioned())
+            boxRect.move(renderBox.offsetForInFlowPosition());
+        stream << " " << boxRect;
+    } else if (is<RenderInline>(*this) && isInFlowPositioned()) {
+        FloatSize inlineOffset = downcast<RenderInline>(*this).offsetForInFlowPosition();
+        stream << "  (" << inlineOffset.width() << ", " << inlineOffset.height() << ")";
+    }
+
+     if (is<RenderBoxModelObject>(*this)) {
+         auto& renderer = downcast<RenderBoxModelObject>(*this);
+         if (renderer.continuation())
+             stream << " continuation->(" << renderer.continuation() << ")";
+     }
+     outputRegionsInformation(stream);
+     stream.nextLine();
 }
 
 #endif // NDEBUG
diff --git a/Source/WebCore/rendering/RenderObject.h b/Source/WebCore/rendering/RenderObject.h
index 3c4f15aa4f1..383bb46b876 100644
--- a/Source/WebCore/rendering/RenderObject.h
+++ b/Source/WebCore/rendering/RenderObject.h
@@ -113,6 +113,9 @@ public:
 
     auto& weakPtrFactory() const { return m_weakFactory; }
 
+    int renderId() const { return m_renderId; }
+    virtual float measureText(int, int) const { return -1; }
+
     RenderTheme& theme() const;
 
     virtual const char* renderName() const = 0;
@@ -203,10 +206,16 @@ public:
     void showNodeTreeForThis() const;
     void showRenderTreeForThis() const;
     void showLineTreeForThis() const;
+    void simplifiedRenderSubtree(TextStream& stream, int depth) const;
+    void renderSubtreeStructure(TextStream& stream) const;
 
     void outputRenderObject(WTF::TextStream&, bool mark, int depth) const;
     void outputRenderSubTreeAndMark(WTF::TextStream&, const RenderObject* markedObject, int depth) const;
+    void outputRenderSubTreeAndMarkStructure(WTF::TextStream&) const;
     void outputRegionsInformation(WTF::TextStream&) const;
+
+    void outputSimplifiedRenderObject(WTF::TextStream&, int depth) const;
+    void outputRenderObjectStructure(WTF::TextStream&) const;
 #endif
 
     bool isPseudoElement() const { return node() && node()->isPseudoElement(); }
@@ -829,6 +838,7 @@ private:
 #endif
 
     Node& m_node;
+    int m_renderId { 0 };
 
     RenderElement* m_parent;
     RenderObject* m_previous;
diff --git a/Source/WebCore/rendering/RenderText.cpp b/Source/WebCore/rendering/RenderText.cpp
index 6ae047c469f..3a9f4839352 100644
--- a/Source/WebCore/rendering/RenderText.cpp
+++ b/Source/WebCore/rendering/RenderText.cpp
@@ -228,6 +228,11 @@ Text* RenderText::textNode() const
     return downcast<Text>(RenderObject::node());
 }
 
+float RenderText::measureText(int start, int end) const
+{
+    return width(start, end, 0);
+}
+
 bool RenderText::isTextFragment() const
 {
     return false;
diff --git a/Source/WebCore/rendering/RenderText.h b/Source/WebCore/rendering/RenderText.h
index e9f727310ae..5ffea9389a8 100644
--- a/Source/WebCore/rendering/RenderText.h
+++ b/Source/WebCore/rendering/RenderText.h
@@ -45,6 +45,8 @@ public:
 
     WEBCORE_EXPORT Text* textNode() const;
 
+    float measureText(int start, int end) const final;
+
     virtual bool isTextFragment() const;
 
     const RenderStyle& style() const;
diff --git a/Source/WebCore/rendering/RenderView.cpp b/Source/WebCore/rendering/RenderView.cpp
index c699d65a26f..b2db6c21c00 100644
--- a/Source/WebCore/rendering/RenderView.cpp
+++ b/Source/WebCore/rendering/RenderView.cpp
@@ -56,6 +56,7 @@
 #include <wtf/IsoMallocInlines.h>
 #include <wtf/SetForScope.h>
 #include <wtf/StackStats.h>
+#include <wtf/text/TextStream.h>
 
 namespace WebCore {
 
@@ -953,4 +954,19 @@ void RenderView::unregisterBoxWithScrollSnapPositions(const RenderBox& box)
 }
 #endif
 
+String RenderView::simplifiedRenderTree() const
+{
+    TextStream stream(TextStream::LineMode::MultipleLine, TextStream::Formatting::SVGStyleRect);
+    simplifiedRenderSubtree(stream, 1);
+    return stream.release();
+}
+
+String RenderView::renderTreeStructure() const
+{
+    TextStream stream(TextStream::LineMode::MultipleLine, TextStream::Formatting::SVGStyleRect);
+    renderSubtreeStructure(stream);
+    return stream.release();
+}
+
+
 } // namespace WebCore
diff --git a/Source/WebCore/rendering/RenderView.h b/Source/WebCore/rendering/RenderView.h
index 294737daad7..e4c7524227d 100644
--- a/Source/WebCore/rendering/RenderView.h
+++ b/Source/WebCore/rendering/RenderView.h
@@ -198,6 +198,9 @@ public:
     bool inHitTesting() const { return m_inHitTesting; }
 #endif
 
+    String simplifiedRenderTree() const;
+    String renderTreeStructure() const;
+
 protected:
     void mapLocalToContainer(const RenderLayerModelObject* repaintContainer, TransformState&, MapCoordinatesFlags, bool* wasFixed) const override;
     const RenderObject* pushMappingToContainer(const RenderLayerModelObject* ancestorToStopAt, RenderGeometryMap&) const override;
diff --git a/Source/WebCore/rendering/SimpleLineLayout.cpp b/Source/WebCore/rendering/SimpleLineLayout.cpp
index 8777dc099b8..702fcc634f4 100644
--- a/Source/WebCore/rendering/SimpleLineLayout.cpp
+++ b/Source/WebCore/rendering/SimpleLineLayout.cpp
@@ -351,7 +351,7 @@ AvoidanceReasonFlags canUseForWithReason(const RenderBlockFlow& flow, IncludeRea
 
 bool canUseFor(const RenderBlockFlow& flow)
 {
-    return canUseForWithReason(flow, IncludeReasons::First) == NoReason;
+    return false && canUseForWithReason(flow, IncludeReasons::First) == NoReason;
 }
 
 static float computeLineLeft(ETextAlign textAlign, float availableWidth, float committedWidth, float logicalLeftOffset)