Move Element.focus()/blur() to HTMLElement and SVGElement.

Source/core/dom/Element.idl

Index: Source/core/dom/Element.idl
diff --git a/Source/core/dom/Element.idl b/Source/core/dom/Element.idl
index 15b035e41c1beb30438cd15e18b7205a5a81477a..f2ae08fd7b756d579f3a992b9989d6ea9bf2d5fd 100644
--- a/Source/core/dom/Element.idl
+++ b/Source/core/dom/Element.idl
@@ -111,10 +111,8 @@
 
     // HTML
     // https://html.spec.whatwg.org/#htmlelement
-    // FIXME: dataset, focus() and blur() should be on HTMLElement. crbug.com/497274
+    // FIXME: dataset should be on HTMLElement.
     [SameObject, PerWorldBindings] readonly attribute DOMStringMap dataset;
-    void focus();
-    void blur();
 
     // Non-standard APIs
     // https://www.w3.org/Bugs/Public/show_bug.cgi?id=19962