Make cluster creation independent of fingerprinting. Keep track of current

Source/core/rendering/TextAutosizer.cpp

Index: Source/core/rendering/TextAutosizer.cpp
diff --git a/Source/core/rendering/TextAutosizer.cpp b/Source/core/rendering/TextAutosizer.cpp
index 94705e6de0121fd1dd7a4e68ced605901742e94b..f793247c7e250e96a028b912f843db4440a9f0f9 100644
--- a/Source/core/rendering/TextAutosizer.cpp
+++ b/Source/core/rendering/TextAutosizer.cpp
@@ -525,6 +525,7 @@ bool TextAutosizer::isIndependentDescendant(const RenderBlock* renderer)
     // from the box's parent (we want to avoid having significantly different
     // width blocks within a cluster, since the narrower blocks would end up
     // larger than would otherwise be necessary).
+    RenderBlock* containingBlock = renderer->containingBlock();
     return renderer->isRenderView()
         || renderer->isFloating()
         || renderer->isOutOfFlowPositioned()
@@ -532,7 +533,7 @@ bool TextAutosizer::isIndependentDescendant(const RenderBlock* renderer)
         || renderer->isTableCaption()
         || renderer->isFlexibleBoxIncludingDeprecated()
         || renderer->hasColumns()
-        || renderer->containingBlock()->isHorizontalWritingMode() != renderer->isHorizontalWritingMode()
+        || (containingBlock && containingBlock->isHorizontalWritingMode() != renderer->isHorizontalWritingMode())
         || renderer->style()->isDisplayReplacedType()
         || renderer->isTextArea()
         || renderer->style()->userModify() != READ_ONLY;