Add UseCounters for Selection methods that take null

third_party/WebKit/Source/core/editing/Selection.idl

Index: third_party/WebKit/Source/core/editing/Selection.idl
diff --git a/third_party/WebKit/Source/core/editing/Selection.idl b/third_party/WebKit/Source/core/editing/Selection.idl
index 5eeeb99e6d610c4a9b5ff602552b66218de406c6..ca677de819c25512c3737dd63b7eaceebc71502d 100644
--- a/third_party/WebKit/Source/core/editing/Selection.idl
+++ b/third_party/WebKit/Source/core/editing/Selection.idl
@@ -58,10 +58,11 @@
     // TODO(philipj): The offset argument should not have a default value.
     [MeasureAs=SelectionExtend, RaisesException] void extend(Node node, optional long offset = 0);
     // TODO(philipj): The arguments should be anchorNode, anchorOffset,
-    // focusNode and focusOffset, and none of them should be optional.
-    [MeasureAs=SelectionSetBaseAndExtent, RaisesException, LegacyInterfaceTypeChecking] void setBaseAndExtent([Default=Undefined] optional Node baseNode,
+    // focusNode and focusOffset, and none of them should be optional or
+    // nullable.
+    [MeasureAs=SelectionSetBaseAndExtent, RaisesException, LegacyInterfaceTypeChecking] void setBaseAndExtent([Default=Undefined] optional Node? baseNode,
                                                                                                               [Default=Undefined] optional long baseOffset,
-                                                                                                              [Default=Undefined] optional Node extentNode,
+                                                                                                              [Default=Undefined] optional Node? extentNode,
                                                                                                               [Default=Undefined] optional long extentOffset);
     [MeasureAs=SelectionSelectAllChildren, RaisesException] void selectAllChildren(Node node);
     [MeasureAs=SelectionDeleteDromDocument, CustomElementCallbacks] void deleteFromDocument();