Avoid requiring a recalc to update compositing state for iframes

LayoutTests/platform/win/fast/flexbox/016-expected.txt

Index: LayoutTests/platform/win/fast/flexbox/016-expected.txt
diff --git a/LayoutTests/platform/win/fast/flexbox/016-expected.txt b/LayoutTests/platform/win/fast/flexbox/016-expected.txt
index 358475d65d98e8bdd771d957ad8389e2c49680fe..2a6703c08c22d1f15adda42763366b994f901f65 100644
--- a/LayoutTests/platform/win/fast/flexbox/016-expected.txt
+++ b/LayoutTests/platform/win/fast/flexbox/016-expected.txt
@@ -11,13 +11,14 @@ layer at (0,0) size 800x585
             text run at (635,0) width 158: "The center should be filled"
             text run at (0,20) width 209: "with an olive-bordered green box. "
             text run at (209,20) width 587: "It should start beneath the header, end above the footer, and fill the width of the browser window."
-        RenderPartObject {IFRAME} at (0,40) size 812x525 [bgcolor=#008000] [border: (10px solid #808000)]
-          layer at (0,0) size 792x505
-            RenderView at (0,0) size 792x505
-          layer at (0,0) size 792x505
-            RenderBlock {HTML} at (0,0) size 792x505
-              RenderBody {BODY} at (8,8) size 776x489
         RenderBlock {DIV} at (0,565) size 800x20
           RenderText {#text} at (0,0) size 631x19
             text run at (0,0) width 388: "This footer should remain at the bottom of the browser window. "
             text run at (388,0) width 243: "It can wrap to multiple lines if necessary."
+layer at (0,40) size 812x525
+  RenderPartObject {IFRAME} at (0,40) size 812x525 [bgcolor=#008000] [border: (10px solid #808000)]
+    layer at (0,0) size 792x505
+      RenderView at (0,0) size 792x505
+    layer at (0,0) size 792x505
+      RenderBlock {HTML} at (0,0) size 792x505
+        RenderBody {BODY} at (8,8) size 776x489