Move backgroundColorOf/backgroundColorShouldBe to shadow-dom.js

LayoutTests/fast/dom/shadow/css-focus-pseudo-match-shadow-host1.html

Index: LayoutTests/fast/dom/shadow/css-focus-pseudo-match-shadow-host1.html
diff --git a/LayoutTests/fast/dom/shadow/css-focus-pseudo-match-shadow-host1.html b/LayoutTests/fast/dom/shadow/css-focus-pseudo-match-shadow-host1.html
index 32e6fa867d5d7a605d10389865bfbefa5379d7f9..0904a4d43f64f368f72f312f3a90985bd02caf5e 100644
--- a/LayoutTests/fast/dom/shadow/css-focus-pseudo-match-shadow-host1.html
+++ b/LayoutTests/fast/dom/shadow/css-focus-pseudo-match-shadow-host1.html
@@ -14,14 +14,6 @@ div#shadow-host:focus {
 <div id="sandbox"></div>
 </body>
 <script>
-function backgroundColorOf(selector) {
-    return window.getComputedStyle(getNodeInTreeOfTrees(selector)).backgroundColor;
-}
-
-function backgroundColorShouldBe(selector, expected) {
-    shouldBeEqualToString('backgroundColorOf(\'' + selector + '\')', expected);
-}
-
 function testWithoutDelegatesFocus()
 {
     debug(':focus and shadow host without delegatesFocus for crbug/479050');