Revert of Re-landing r170008, removing prefixed Shadow DOM APIs in Element.

LayoutTests/inspector/elements/styles/shadow-dom-rules.html

Index: LayoutTests/inspector/elements/styles/shadow-dom-rules.html
diff --git a/LayoutTests/inspector/elements/styles/shadow-dom-rules.html b/LayoutTests/inspector/elements/styles/shadow-dom-rules.html
index c1324c89786545a86e3bd13f5f47e2d083072396..308e4deb1fd0735998d2d40a5b3aa09103cea4d7 100644
--- a/LayoutTests/inspector/elements/styles/shadow-dom-rules.html
+++ b/LayoutTests/inspector/elements/styles/shadow-dom-rules.html
@@ -7,7 +7,7 @@
 function createShadowRoot()
 {
     var template = document.querySelector('#tmpl');
-    var root = document.querySelector('#host').createShadowRoot();
+    var root = document.querySelector('#host').webkitCreateShadowRoot();
     root.appendChild(template.content.cloneNode(true));
 }