DevTools: fix author shadow dom inspection mode, speacial-case ua. Fix crash from the bug.

LayoutTests/inspector/elements/update-shadowdom.html

Index: LayoutTests/inspector/elements/update-shadowdom.html
diff --git a/LayoutTests/inspector/elements/update-shadowdom.html b/LayoutTests/inspector/elements/update-shadowdom.html
index 3ae3c90525d16c371130a81e6ab096087fee98d7..ceec74f04576ebdcce7cd3f64b2c7d756910f5a6 100644
--- a/LayoutTests/inspector/elements/update-shadowdom.html
+++ b/LayoutTests/inspector/elements/update-shadowdom.html
@@ -8,11 +8,6 @@ function updateShadowDOM()
     shadowRoot.removeChild(shadowRoot.firstChild);
 }
 
-function initialize_shadowSettings()
-{
-    WebInspector.settings.showShadowDOM.set(true);
-}
-
 function test()
 {
     InspectorTest.expandElementsTree(function() {
@@ -20,7 +15,6 @@ function test()
             InspectorTest.expandElementsTree(function() {
                 var containerElem = InspectorTest.expandedNodeWithId('container');
                 InspectorTest.dumpElementsTree(containerElem);
-                WebInspector.settings.showShadowDOM.set(false);
                 InspectorTest.completeTest();
             });
         });