Convert first letter into a pseudo element.

Source/core/dom/RenderTreeBuilder.cpp

Index: Source/core/dom/RenderTreeBuilder.cpp
diff --git a/Source/core/dom/RenderTreeBuilder.cpp b/Source/core/dom/RenderTreeBuilder.cpp
index 7572603e73763b11ab81fd4bb3a7ae75ca1aa8b9..faa45502740da114ee05cbef3e76139de3e905c1 100644
--- a/Source/core/dom/RenderTreeBuilder.cpp
+++ b/Source/core/dom/RenderTreeBuilder.cpp
@@ -29,8 +29,10 @@
 #include "core/HTMLNames.h"
 #include "core/SVGNames.h"
 #include "core/css/resolver/StyleResolver.h"
+#include "core/dom/FirstLetterPseudoElement.h"
 #include "core/dom/Fullscreen.h"
 #include "core/dom/Node.h"
+#include "core/dom/PseudoElement.h"
 #include "core/dom/Text.h"
 #include "core/rendering/RenderFullScreen.h"
 #include "core/rendering/RenderObject.h"
@@ -41,6 +43,30 @@
 
 namespace blink {
 
+RenderTreeBuilder::RenderTreeBuilder(Node* node, RenderStyle* style)
+    : m_node(node)
+    , m_renderingParent(nullptr)
+    , m_style(style)
+{
+    ASSERT(!node->renderer());
+    ASSERT(node->needsAttach());
+    ASSERT(node->document().inStyleRecalc());
+
+    // FIXME: We should be able to ASSERT(node->inActiveDocument()) but childrenChanged is called
+    // before ChildNodeInsertionNotifier in ContainerNode's methods and some implementations
+    // will trigger a layout inside childrenChanged.
+    // Mainly HTMLTextAreaElement::childrenChanged calls HTMLTextFormControlElement::setSelectionRange
+    // which does an updateLayoutIgnorePendingStylesheets.
+
+    Element* element = node->isElementNode() ? toElement(node) : 0;
+    if (element && element->isFirstLetterPseudoElement()) {
+        if (RenderObject* nextRenderer = FirstLetterPseudoElement::firstLetterTextRenderer(*element))
+            m_renderingParent = nextRenderer->parent();
+    } else if (ContainerNode* containerNode = NodeRenderingTraversal::parent(node, &m_parentDetails)) {
+        m_renderingParent = containerNode->renderer();
+    }
+}
+
 RenderObject* RenderTreeBuilder::nextRenderer() const
 {
     ASSERT(m_renderingParent);
@@ -50,8 +76,11 @@ RenderObject* RenderTreeBuilder::nextRenderer() const
     if (element && element->isInTopLayer())
         return NodeRenderingTraversal::nextInTopLayer(element);
 
+    if (element && element->isFirstLetterPseudoElement())
+        return FirstLetterPseudoElement::firstLetterTextRenderer(*element);
+
     // Avoid an O(N^2) walk over the children when reattaching all children of a node.
-    if (m_renderingParent->needsAttach())
+    if (m_renderingParent->node() && m_renderingParent->node()->needsAttach())
         return 0;
 
     return NodeRenderingTraversal::nextSiblingRenderer(m_node);
@@ -63,15 +92,15 @@ RenderObject* RenderTreeBuilder::parentRenderer() const
 
     Element* element = m_node->isElementNode() ? toElement(m_node) : 0;
 
-    if (element && m_renderingParent->renderer()) {
-        // FIXME: Guarding this by m_renderingParent->renderer() isn't quite right as the spec for
+    if (element && m_renderingParent) {
+        // FIXME: Guarding this by m_renderingParent isn't quite right as the spec for
         // top layer only talks about display: none ancestors so putting a <dialog> inside an
         // <optgroup> seems like it should still work even though this check will prevent it.
         if (element->isInTopLayer())
             return m_node->document().renderView();
     }
 
-    return m_renderingParent->renderer();
+    return m_renderingParent;
 }
 
 bool RenderTreeBuilder::shouldCreateRenderer() const
@@ -80,11 +109,12 @@ bool RenderTreeBuilder::shouldCreateRenderer() const
         return false;
     if (m_node->isSVGElement()) {
         // SVG elements only render when inside <svg>, or if the element is an <svg> itself.
-        if (!isSVGSVGElement(*m_node) && !m_renderingParent->isSVGElement())
+        if (!isSVGSVGElement(*m_node) && (!m_renderingParent->node() || !m_renderingParent->node()->isSVGElement()))
             return false;
         if (!toSVGElement(m_node)->isValid())
             return false;
     }
+
     RenderObject* parentRenderer = this->parentRenderer();
     if (!parentRenderer)
         return false;