[IFC] Cache canUseSimplifiedTextMeasuring on RenderText

https://bugs.webkit.org/show_bug.cgi?id=260426

Reviewed by Antti Koivisto.

1. Computing canUseSimplifiedTextMeasuring is an expensive operation (it may iterate through all the glyphs of the text content)
2. We used to cache this information on RenderText (see 260675@main) and now it's computed at BoxTree building.
3. Due to eager (IFC integration) invalidation, we destroy BoxTree in cases where we still keep associated RenderText renderers alive.

~10% progression on PerformanceTests/Layout/line-layout-preferred-width-break-all.html

* PerformanceTests/Layout/line-layout.html:
* Source/WebCore/layout/integration/LayoutIntegrationBoxTree.cpp:
(WebCore::LayoutIntegration::BoxTree::createLayoutBox):
* Source/WebCore/rendering/RenderText.cpp:
(WebCore::RenderText::setRenderedText):
* Source/WebCore/rendering/RenderText.h:
(WebCore::RenderText::setCanUseSimplifiedTextMeasuring):
(WebCore::RenderText::canUseSimplifiedTextMeasuring const):

Canonical link: https://commits.webkit.org/267081@main

Source/WebCore/layout/integration/LayoutIntegrationBoxTree.cpp

@@ -193,8 +193,12 @@ UniqueRef<Layout::Box> BoxTree::createLayoutBox(RenderObject& renderer)
             ? (isCombinedText ? textRenderer.originalText() : textRenderer.text())
             : RenderBlock::updateSecurityDiscCharacters(style, isCombinedText ? textRenderer.originalText() : textRenderer.text());
         auto canUseSimpleFontCodePath = textRenderer.canUseSimpleFontCodePath();
-        auto canUseSimplifiedTextMeasuring = canUseSimpleFontCodePath && Layout::TextUtil::canUseSimplifiedTextMeasuring(text, style, firstLineStyle.get());
-        return makeUniqueRef<Layout::InlineTextBox>(text, isCombinedText, canUseSimplifiedTextMeasuring, canUseSimpleFontCodePath, WTFMove(style), WTFMove(firstLineStyle));
+        auto canUseSimplifiedTextMeasuring = textRenderer.canUseSimplifiedTextMeasuring();
+        if (!canUseSimplifiedTextMeasuring) {
+            canUseSimplifiedTextMeasuring = canUseSimpleFontCodePath && Layout::TextUtil::canUseSimplifiedTextMeasuring(text, style, firstLineStyle.get());
+            textRenderer.setCanUseSimplifiedTextMeasuring(*canUseSimplifiedTextMeasuring);
+        }
+        return makeUniqueRef<Layout::InlineTextBox>(text, isCombinedText, *canUseSimplifiedTextMeasuring, canUseSimpleFontCodePath, WTFMove(style), WTFMove(firstLineStyle));
     }
 
     auto& renderElement = downcast<RenderElement>(renderer);

Source/WebCore/rendering/RenderText.cpp

@@ -92,6 +92,7 @@ struct SameSizeAsRenderText : public RenderObject {
     float widths[2];
     std::optional<float> minWidth;
     std::optional<float> maxWidth;
+    std::optional<bool> canUseSimplifiedTextMeasuring;
     String text;
 };
 
@@ -328,6 +329,8 @@ void RenderText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyl
     const RenderStyle& newStyle = style();
     if (!oldStyle)
         initiateFontLoadingByAccessingGlyphDataIfApplicable(m_text, newStyle.fontCascade());
+    if (oldStyle && oldStyle->fontCascade() != newStyle.fontCascade())
+        m_canUseSimplifiedTextMeasuring = { };
 
     bool needsResetText = false;
     if (!oldStyle) {
@@ -1583,7 +1586,8 @@ void RenderText::setRenderedText(const String& newText)
 
     m_containsOnlyASCII = text().containsOnlyASCII();
     m_canUseSimpleFontCodePath = computeCanUseSimpleFontCodePath();
-
+    m_canUseSimplifiedTextMeasuring = { };
+
     if (m_text != originalText) {
         originalTextMap().set(this, originalText);
         m_originalTextDiffersFromRendered = true;

Source/WebCore/rendering/RenderText.h

@@ -184,6 +184,9 @@ class RenderText : public RenderObject {
 
     void resetMinMaxWidth();
 
+    void setCanUseSimplifiedTextMeasuring(bool canUseSimplifiedTextMeasuring) { m_canUseSimplifiedTextMeasuring = canUseSimplifiedTextMeasuring; }
+    std::optional<bool> canUseSimplifiedTextMeasuring() const { return m_canUseSimplifiedTextMeasuring; }
+
 protected:
     virtual void computePreferredLogicalWidths(float leadWidth, bool forcedMinMaxWidthComputation = false);
     void willBeDestroyed() override;
@@ -252,6 +255,7 @@ class RenderText : public RenderObject {
 #endif
     std::optional<float> m_minWidth;
     std::optional<float> m_maxWidth;
+    std::optional<bool> m_canUseSimplifiedTextMeasuring { };
     float m_beginMinWidth { 0 };
     float m_endMinWidth { 0 };