Range.deleteContents shouldn't throw HierarchyRequestError on doctype

Source/core/dom/Range.cpp

Index: Source/core/dom/Range.cpp
diff --git a/Source/core/dom/Range.cpp b/Source/core/dom/Range.cpp
index 0b87825708b4dbcb40361fdc0e8c4fc0b6beb687..0a9710b9ea4100a0a83983e68679b391ab0c82da 100644
--- a/Source/core/dom/Range.cpp
+++ b/Source/core/dom/Range.cpp
@@ -462,9 +462,7 @@ bool Range::boundaryPointsValid() const
 
 void Range::deleteContents(ExceptionState& exceptionState)
 {
-    checkDeleteExtract(exceptionState);
-    if (exceptionState.hadException())
-        return;
+    ASSERT(boundaryPointsValid());
 
     {
         EventQueueScope eventQueueScope;