Make first-letter style to work with editing

Source/core/dom/PositionIterator.cpp

Index: Source/core/dom/PositionIterator.cpp
diff --git a/Source/core/dom/PositionIterator.cpp b/Source/core/dom/PositionIterator.cpp
index 34328d65479d94e827eb3b8d545dc77dd3e3525b..10e2272d25bcc2daf3a2f02fbac982633331295e 100644
--- a/Source/core/dom/PositionIterator.cpp
+++ b/Source/core/dom/PositionIterator.cpp
@@ -31,6 +31,7 @@
 #include "core/editing/htmlediting.h"
 #include "core/html/HTMLHtmlElement.h"
 #include "core/rendering/RenderBlock.h"
+#include "core/rendering/RenderTextFragment.h"
 
 namespace WebCore {
 
@@ -103,6 +104,14 @@ void PositionIterator::decrement()
     }
 }
 
+RenderObject* PositionIterator::renderer() const
+{
+    if (!m_anchorNode)
+        return 0;
+    Position pos = *this;
+    return pos.renderer();
+}
+
 bool PositionIterator::atStart() const
 {
     if (!m_anchorNode)
@@ -144,7 +153,7 @@ bool PositionIterator::isCandidate() const
     if (!m_anchorNode)
         return false;
 
-    RenderObject* renderer = m_anchorNode->renderer();
+    RenderObject* renderer = this->renderer();
     if (!renderer)
         return false;