Convert first letter into a pseudo element.

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index e859321b551d452b95a8777c81e6afabea8cb9e6..c6ccd3b8cab62662ec032e1c7667b2701418800b 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -56,6 +56,7 @@
 #include "core/dom/ElementRareData.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/ExceptionCode.h"
+#include "core/dom/FirstLetterHelper.h"
 #include "core/dom/Fullscreen.h"
 #include "core/dom/MutationObserverInterestGroup.h"
 #include "core/dom/MutationRecord.h"
@@ -66,6 +67,7 @@
 #include "core/dom/RenderTreeBuilder.h"
 #include "core/dom/ScriptableDocumentParser.h"
 #include "core/dom/SelectorQuery.h"
+#include "core/dom/StyleChangeReason.h"
 #include "core/dom/StyleEngine.h"
 #include "core/dom/Text.h"
 #include "core/dom/custom/CustomElement.h"
@@ -103,6 +105,7 @@
 #include "core/page/Page.h"
 #include "core/page/PointerLockController.h"
 #include "core/rendering/RenderLayer.h"
+#include "core/rendering/RenderTextFragment.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/compositing/RenderLayerCompositor.h"
 #include "core/svg/SVGDocumentExtensions.h"
@@ -1346,6 +1349,11 @@ void Element::attach(const AttachContext& context)
     createPseudoElementIfNeeded(AFTER);
     createPseudoElementIfNeeded(BACKDROP);
 
+    // We create the first-letter element after the :before, :after and
+    // children are attached because the first letter text could come
+    // from any of them.
+    createPseudoElementIfNeeded(FIRST_LETTER);
+
     if (hasRareData() && !renderer()) {
         if (ActiveAnimations* activeAnimations = elementRareData()->activeAnimations()) {
             activeAnimations->cssAnimations().cancel();
@@ -1505,6 +1513,12 @@ void Element::recalcStyle(StyleRecalcChange change, Text* nextTextSibling)
         updatePseudoElement(AFTER, change);
         updatePseudoElement(BACKDROP, change);
 
+        // If our children have changed then we need to force the first-letter
+        // checks as we don't know if they effected the first letter or not.
+        // This can be seen when a child transitions from floating to
+        // non-floating we have to take it into account for the first letter.
+        updatePseudoElement(FIRST_LETTER, childNeedsStyleRecalc() ? Force : change);
+
         clearChildNeedsStyleRecalc();
     }
 
@@ -2486,8 +2500,18 @@ void Element::updatePseudoElement(PseudoId pseudoId, StyleRecalcChange change)
 {
     ASSERT(!needsStyleRecalc());
     PseudoElement* element = pseudoElement(pseudoId);
+
     if (element && (change == UpdatePseudoElements || element->shouldCallRecalcStyle(change))) {
 
+        // If we're updating first letter, and the current first letter renderer
+        // is not the same as the one we're currently using we need to re-create
+        // the first letter renderer.
+        if (pseudoId == FIRST_LETTER && FirstLetterHelper::firstLetterTextRenderer(*element) != element->remainingTextRenderer()) {
+            elementRareData()->setPseudoElement(pseudoId, nullptr);
+            createPseudoElementIfNeeded(pseudoId);
+            return;
+        }
+
         // Need to clear the cached style if the PseudoElement wants a recalc so it
         // computes a new style.
         if (element->needsStyleRecalc())
@@ -2499,13 +2523,21 @@ void Element::updatePseudoElement(PseudoId pseudoId, StyleRecalcChange change)
         element->recalcStyle(change == UpdatePseudoElements ? Force : change);
 
         // Wait until our parent is not displayed or pseudoElementRendererIsNeeded
-        // is false, otherwise we could continously create and destroy PseudoElements
+        // is false, otherwise we could continuously create and destroy PseudoElements
         // when RenderObject::isChildAllowed on our parent returns false for the
         // PseudoElement's renderer for each style recalc.
         if (!renderer() || !pseudoElementRendererIsNeeded(renderer()->getCachedPseudoStyle(pseudoId)))
             elementRareData()->setPseudoElement(pseudoId, nullptr);
     } else if (change >= UpdatePseudoElements) {
-        createPseudoElementIfNeeded(pseudoId);
+        // We have a first-letter pseudoElement, but we no longer should have one.
+        // This can happen if we change to a float, for example. We need to cleanup the
+        // first-letter pseudoElement and then fix the text of the original remaining
+        // text renderer.
+        // This can be seen in Test 7 of fast/css/first-letter-removed-added.html
+        if (pseudoId == FIRST_LETTER && element && !FirstLetterHelper::firstLetterTextRenderer(*element))
+            elementRareData()->setPseudoElement(pseudoId, nullptr);
+        else
+            createPseudoElementIfNeeded(pseudoId);
     }
 }