Make compositor and blink talk in fractional scroll offset

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 443 matching lines @@
     RenderLayerCompositor* innerCompositor = innerRenderView->compositor();
     ASSERT_TRUE(innerCompositor->inCompositingMode());
     ASSERT_TRUE(innerCompositor->scrollLayer());
 
     GraphicsLayer* scrollLayer = innerCompositor->scrollLayer();
     ASSERT_EQ(innerFrameView, scrollLayer->scrollableArea());
 
     WebLayer* webScrollLayer = scrollLayer->platformLayer();
     ASSERT_TRUE(webScrollLayer->scrollable());
 
     int expectedScrollPosition = 958 + (innerFrameView->verticalScrollbar()->isOverlayScrollbar() ? 0 : 15);

[Rick Byers, 2014/10/04 00:04:25]

again, let's use a non-integer value

[Yufeng Shen (Slow to review), 2014/10/06 17:54:58]

hmm, not sure about this one. This test is testing the behavior that
the rtl page is scrolled to the rightmost upon layout, there is no actual
scrolling happening and the number is derived from the width/height of
frame/iframe.

[Rick Byers, 2014/10/06 21:11:30]

Ah, I hadn't looked that deeply.  Looks fine - thanks.

-    ASSERT_EQ(expectedScrollPosition, webScrollLayer->scrollPosition().x);
+    ASSERT_EQ(expectedScrollPosition, webScrollLayer->scrollPositionDouble().x);
 }
 
 TEST_F(ScrollingCoordinatorChromiumTest, setupScrollbarLayerShouldNotCrash)
 {
     registerMockedHttpURLLoad("setup_scrollbar_layer_crash.html");
     navigateTo(m_baseURL + "setup_scrollbar_layer_crash.html");
     forceFullCompositingUpdate();
     // This test document setup an iframe with scrollbars, then switch to
     // an empty document by javascript.
 }
 
 } // namespace