Revert of Reland r165710 "Replace RenderFullScreen with top layer"

Source/core/css/fullscreen.css

Index: Source/core/css/fullscreen.css
diff --git a/Source/core/css/fullscreen.css b/Source/core/css/fullscreen.css
index 15d0a529a5e5cce0bd26ccfe3578baea18b3c5fc..5ea5f06c2f071bf792657394e4c80fcec9e05b92 100644
--- a/Source/core/css/fullscreen.css
+++ b/Source/core/css/fullscreen.css
@@ -1,27 +1,6 @@
 :-webkit-full-screen {
     background-color: white;
-}
-
-:not(:root):-webkit-full-screen {
-    position: fixed;
-    top: 0;
-    right: 0;
-    bottom: 0;
-    left: 0;
-    margin: 0;
-    box-sizing: border-box;
-    width: 100%;
-    height: 100%;
-    object-fit: contain;
-}
-
-:-webkit-full-screen::backdrop {
-    position: fixed;
-    top: 0;
-    right: 0;
-    bottom: 0;
-    left: 0;
-    background: black;
+    z-index: 2147483647 !important;
 }
 
 :root:-webkit-full-screen-document:not(:-webkit-full-screen), :root:-webkit-full-screen-ancestor {