Currently we only composite fixed position elements if we are on High DPI devices. This fix allows …

Source/web/tests/ScrollingCoordinatorTest.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 577 matching lines @@
 {
     webViewImpl()->settings()->setPreferCompositingToLCDTextEnabled(false);
     registerMockedHttpURLLoad("fixed-position-losing-backing.html");
     navigateTo(m_baseURL + "fixed-position-losing-backing.html");
     forceFullCompositingUpdate();
 
     WebLayer* scrollLayer = frame()->page()->deprecatedLocalMainFrame()->view()->layerForScrolling()->platformLayer();
     Document* document = frame()->document();
     Element* fixedPos = document->getElementById("fixed");
 
-    EXPECT_TRUE(static_cast<LayoutBoxModelObject*>(fixedPos->layoutObject())->layer()->hasCompositedDeprecatedPaintLayerMapping());
+    ASSERT_EQ(PaintsIntoOwnBacking, static_cast<LayoutBoxModelObject*>(fixedPos->layoutObject())->layer()->compositingState());
     EXPECT_FALSE(scrollLayer->shouldScrollOnMainThread());
 
-    fixedPos->setInlineStyleProperty(CSSPropertyTransform, CSSValueNone);
+    fixedPos->setInlineStyleProperty(CSSPropertyBackground, "rgba(255, 255, 0, 0.99)");
     forceFullCompositingUpdate();
 
-    EXPECT_FALSE(static_cast<LayoutBoxModelObject*>(fixedPos->layoutObject())->layer()->hasCompositedDeprecatedPaintLayerMapping());
+    ASSERT_EQ(NotComposited, static_cast<LayoutBoxModelObject*>(fixedPos->layoutObject())->layer()->compositingState());
     EXPECT_TRUE(scrollLayer->shouldScrollOnMainThread());
 }
 
 } // namespace blink