DevTools: Make replace checkbox id in SearchableView unique.

LayoutTests/inspector/editor/text-editor-search-replace.html

Index: LayoutTests/inspector/editor/text-editor-search-replace.html
diff --git a/LayoutTests/inspector/editor/text-editor-search-replace.html b/LayoutTests/inspector/editor/text-editor-search-replace.html
index 00e9b487a81043c09d519b23cd720ff00ffb9ca8..39df048eae9142d3385206ebfaaeadf6ed9236eb 100644
--- a/LayoutTests/inspector/editor/text-editor-search-replace.html
+++ b/LayoutTests/inspector/editor/text-editor-search-replace.html
@@ -14,8 +14,9 @@ function test()
 
     function showReplaceField()
     {
-        WebInspector.panels.sources.searchableView().showSearchField();
-        document.getElementById("search-replace-trigger").click();
+        var searchableView = WebInspector.panels.sources.searchableView();
+        searchableView.showSearchField();
+        searchableView._replaceCheckboxElement.click();
     }
 
     function runReplaceAll(searchValue, replaceValue)