Ensure clean layout before calling TextIterator::rangeLength in editing code

third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp

Index: third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp
diff --git a/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp b/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp
index 8dfe33c483607d7cf01dacea07d2d2dfea5de9a0..4d28398ca07176da9992bb687dcbd5dddebebcb4 100644
--- a/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp
+++ b/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp
@@ -1299,6 +1299,9 @@ void CompositeEditCommand::moveParagraphs(const VisiblePosition& startOfParagrap
             bool startInParagraph = comparePositions(visibleStart, startOfParagraphToMove) >= 0;
             bool endInParagraph = comparePositions(visibleEnd, endOfParagraphToMove) <= 0;
 
+            // TextIterator::rangeLength requires clean layout.
+            document().updateStyleAndLayoutIgnorePendingStylesheets();
+
             startIndex = 0;
             if (startInParagraph)
                 startIndex = TextIterator::rangeLength(startOfParagraphToMove.toParentAnchoredPosition(), visibleStart.toParentAnchoredPosition(), true);