ASSERT on renderer lifecycle

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 6236af469fc215673ba017bf059b37b293c38de4..ed2e875e561500f58a65b631bde52fdbcd09f092 100644
--- a/Source/core/rendering/RenderBlock.cpp
+++ b/Source/core/rendering/RenderBlock.cpp
@@ -4036,8 +4036,12 @@ void RenderBlock::createFirstLetterRenderer(RenderObject* firstLetterBlock, Rend
     else
         firstLetter = RenderBlockFlow::createAnonymous(&document());
     firstLetter->setStyle(pseudoStyle);
-    firstLetterContainer->addChild(firstLetter, currentChild);
 
+    // FIXME: The first letter code should not modify the tree outside of recalc
+    // style. crbug.com/370458

[leviw_travelin_and_unemployed, 2014/05/06 18:41:29]

I'd vote for a slightly broader comment to the effect that we shouldn't modify
the render tree during layout, not that we should only modify it in recalc
style.

[dsinclair, 2014/05/07 16:24:40]

Done.

+    DeprecatedDisableModifyRenderTreeStructureAsserts disabler;
+
+    firstLetterContainer->addChild(firstLetter, currentChild);
     RenderText* textObj = toRenderText(currentChild);
 
     // The original string is going to be either a generated content string or a DOM node's