Simplify CompositingReasonFinder::requiresCompositingForFrame

LayoutTests/compositing/iframes/iframe-size-to-zero.html

Index: LayoutTests/compositing/iframes/iframe-size-to-zero.html
diff --git a/LayoutTests/compositing/iframes/iframe-size-to-zero.html b/LayoutTests/compositing/iframes/iframe-size-to-zero.html
index f1faf7ffaa03b86fd3771662cb4bda714a64b6f2..76fbe4383df86d66661e2e901867269c36e93946 100644
--- a/LayoutTests/compositing/iframes/iframe-size-to-zero.html
+++ b/LayoutTests/compositing/iframes/iframe-size-to-zero.html
@@ -46,10 +46,10 @@
             if (window.testRunner) {
                 var haveLayers = window.internals.layerTreeAsText(document) != "";
                 var result;
-                if (hadLayers && !haveLayers)
-                  result = "PASS: had layers, and now do not";
+                if (hadLayers && haveLayers)
+                  result = "PASS: Had layers before and after";
                 else
-                  result = "FAIL: layers should have gone. hadLayers = " + hadLayers + ", haveLayers = " + haveLayers;
+                  result = "FAIL: Layers should have stayed. hadLayers = " + hadLayers + ", haveLayers = " + haveLayers;
                 document.getElementById('result').innerHTML = result;
                 testRunner.notifyDone();
             }