Let FrameSelection::localCaretRect on a text input field avoid synchronous layout.

Source/core/editing/VisibleUnits.h

Index: Source/core/editing/VisibleUnits.h
diff --git a/Source/core/editing/VisibleUnits.h b/Source/core/editing/VisibleUnits.h
index f07826032ed9218e0bb717c0933e79dcf2b07f94..665f55fcc93de27eefb6a627f23887b817473b6c 100644
--- a/Source/core/editing/VisibleUnits.h
+++ b/Source/core/editing/VisibleUnits.h
@@ -31,6 +31,9 @@
 
 namespace blink {
 
+class LayoutRect;
+class PositionWithAffinity;
+class RenderObject;
 class Node;
 class VisiblePosition;
 
@@ -93,6 +96,9 @@ VisiblePosition startOfEditableContent(const VisiblePosition&);
 VisiblePosition endOfEditableContent(const VisiblePosition&);
 bool isEndOfEditableOrNonEditableContent(const VisiblePosition&);
 
+// Rect is local to the returned renderer
+LayoutRect localCaretRectOfPosition(const PositionWithAffinity&, RenderObject*&);
+
 } // namespace blink
 
 #endif // VisibleUnits_h