Pass integer scroll position to CC if frameView has non-layered viewport constrained objects

Source/web/tests/ScrollingCoordinatorChromiumTest.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 148 matching lines @@
         return 0;
     if (!layer->hasCompositedLayerMapping())
         return 0;
     CompositedLayerMapping* compositedLayerMapping = layer->compositedLayerMapping();
     GraphicsLayer* graphicsLayer = compositedLayerMapping->mainGraphicsLayer();
     if (!graphicsLayer)
         return 0;
     return graphicsLayer->platformLayer();
 }
 
+
+TEST_F(ScrollingCoordinatorChromiumTest, fractionalScrollingNonLayerFixedPosition)
+{
+    registerMockedHttpURLLoad("fractional-scroll-fixed-position.html");
+    navigateTo(m_baseURL + "fractional-scroll-fixed-position.html");
+    // Prevent fixed-position element from getting its own layer.
+    webViewImpl()->settings()->setPreferCompositingToLCDTextEnabled(false);
+    forceFullCompositingUpdate();
+
+    FrameView* frameView = frame()->view();
+    frameView->scrollTo(DoublePoint(1.5, 1.5));
+    WebLayer* rootScrollLayer = getRootScrollLayer();
+    // Scroll on main if there is non-composited fixed position element.
+    // And the containing scroll layer should not get fractional scroll offset.
+    ASSERT_TRUE(rootScrollLayer->shouldScrollOnMainThread());
+    ASSERT_EQ(1.0, rootScrollLayer->scrollPositionDouble().x);
+    ASSERT_EQ(1.0, rootScrollLayer->scrollPositionDouble().y);
+    ASSERT_EQ(0.0, rootScrollLayer->position().x);
+    ASSERT_EQ(0.0, rootScrollLayer->position().y);
+}
+
 TEST_F(ScrollingCoordinatorChromiumTest, fastScrollingForFixedPosition)
 {
     registerMockedHttpURLLoad("fixed-position.html");
     navigateTo(m_baseURL + "fixed-position.html");
     forceFullCompositingUpdate();
 
     // Fixed position should not fall back to main thread scrolling.
     WebLayer* rootScrollLayer = getRootScrollLayer();
     ASSERT_FALSE(rootScrollLayer->shouldScrollOnMainThread());
 
@@ skipping 322 matching lines @@
     WebLayer* contentsLayer = scrollbarGraphicsLayer->contentsLayer();
     ASSERT_TRUE(contentsLayer);
 
     // After scrollableAreaScrollbarLayerDidChange,
     // if the main frame's scrollbarLayer is opaque,
     // contentsLayer should be opaque too.
     ASSERT_EQ(platformLayer->opaque(), contentsLayer->opaque());
 }
 
 } // namespace