Update the first letter when the first line is changed by adding a new text at its start.

Source/core/rendering/RenderBlock.cpp

Index: Source/core/rendering/RenderBlock.cpp
diff --git a/Source/core/rendering/RenderBlock.cpp b/Source/core/rendering/RenderBlock.cpp
index fbf39328a2d0617a72cd8936225e39b99c16b7eb..d2ab0c0081ce5f779b3c4ce1a54e0988e041b256 100644
--- a/Source/core/rendering/RenderBlock.cpp
+++ b/Source/core/rendering/RenderBlock.cpp
@@ -29,6 +29,7 @@
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/OverflowEvent.h"
+#include "core/dom/Text.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/editing/Editor.h"
 #include "core/editing/FrameSelection.h"
@@ -6724,8 +6725,6 @@ void RenderBlock::updateFirstLetter()
     if (style()->styleType() == FIRST_LETTER)
         return;
 
-    // FIXME: We need to destroy the first-letter object if it is no longer the first child. Need to find
-    // an efficient way to check for that situation though before implementing anything.
     RenderObject* firstLetterBlock = findFirstLetterBlock(this);
     if (!firstLetterBlock)
         return;
@@ -6756,9 +6755,22 @@ void RenderBlock::updateFirstLetter()
     if (!currChild)
         return;
 
-    // If the child already has style, then it has already been created, so we just want
-    // to update it.
     if (currChild->parent()->style()->styleType() == FIRST_LETTER) {
+        // Destroy the first-letter object if it is no longer the first child.
+        RenderObject* remainingText = currChild->parent()->nextSibling();

[esprehn, 2013/09/09 21:22:57]

How do you know the currentCuild->parent() has a nextSibling and that it's not
wrapped in an anonymous thing?

[joone, 2013/09/09 22:36:25]

The currentChild is the firstLetter(RenderTextFragment) so its
parent(RenderInLine)'s next sibling should be the
remainingText(RenderTextFragment).The RenderInLine has the firstLetter object.
You can understand this from the createFirstLetterRenderer method. 

+        if (currChild->node() != remainingText->node()) {
+            LayoutStateDisabler layoutStateDisabler(view());
+
+            RenderObject* oldRemainingText = toRenderBoxModelObject(currChild->parent())->firstLetterRemainingText();
+            if (oldRemainingText)
+                toRenderText(oldRemainingText)->setText(toText(oldRemainingText->node())->data().impl());
+
+            createFirstLetterRenderer(firstLetterBlock, remainingText);

[esprehn, 2013/09/09 21:22:57]

What destroyed the original RenderTextFragment that was there?

[joone, 2013/09/09 22:36:25]

When setting a new text to RenderTextFragment(RemainingText), the firstLetter's
parent(RenderInLine) is destroyed. You can see the code in
RenderTextFragment::setText

+            return;
+        }
+
+        // If the child already has style, then it has already been created, so we just want
+        // to update it.
         updateFirstLetterStyle(firstLetterBlock, currChild);
         return;
     }