Remove out-of-date FIXME on collapsing margins

Source/core/rendering/RenderBlockFlow.cpp

Index: Source/core/rendering/RenderBlockFlow.cpp
diff --git a/Source/core/rendering/RenderBlockFlow.cpp b/Source/core/rendering/RenderBlockFlow.cpp
index 88382978d73aba5ee0d15496d799b5ce8db3f2a9..444a6aa63b1f7b0f80e7ac515ad37cad53989ea1 100644
--- a/Source/core/rendering/RenderBlockFlow.cpp
+++ b/Source/core/rendering/RenderBlockFlow.cpp
@@ -1300,9 +1300,6 @@ LayoutUnit RenderBlockFlow::clearFloatsIfNeeded(RenderBox* child, MarginInfo& ma
     if (marginInfo.canCollapseWithMarginBefore()) {
         // We can no longer collapse with the top of the block since a clear
         // occurred. The empty blocks collapse into the cleared block.
-        // FIXME: This isn't quite correct. Need clarification for what to do
-        // if the height the cleared block is offset by is smaller than the
-        // margins involved.
         setMaxMarginBeforeValues(oldTopPosMargin, oldTopNegMargin);
         marginInfo.setAtBeforeSideOfBlock(false);