Disable fractional scroll feature by default

third_party/WebKit/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 135 matching lines @@
 
     // Main scrolling should be enabled with the setting override.
     WebLayer* rootScrollLayer = getRootScrollLayer();
     ASSERT_TRUE(rootScrollLayer->scrollable());
     ASSERT_TRUE(rootScrollLayer->shouldScrollOnMainThread());
 }
 
 
 TEST_F(ScrollingCoordinatorTest, fastFractionalScrollingDiv)
 {
+    bool origFractionalOffsetsEnabled = RuntimeEnabledFeatures::fractionalScrollOffsetsEnabled();
+    RuntimeEnabledFeatures::setFractionalScrollOffsetsEnabled(true);
+
     registerMockedHttpURLLoad("fractional-scroll-div.html");
     navigateTo(m_baseURL + "fractional-scroll-div.html");
     forceFullCompositingUpdate();
 
     Document* document = frame()->document();
     Element* scrollableElement = document->getElementById("scroller");
     DCHECK(scrollableElement);
 
     scrollableElement->setScrollTop(1.0);
     scrollableElement->setScrollLeft(1.0);
     forceFullCompositingUpdate();
 
     // Make sure the fractional scroll offset change 1.0 -> 1.2 gets propagated
     // to compositor.
     scrollableElement->setScrollTop(1.2);
     scrollableElement->setScrollLeft(1.2);
     forceFullCompositingUpdate();
 
     LayoutObject* layoutObject = scrollableElement->layoutObject();
     ASSERT_TRUE(layoutObject->isBox());
     LayoutBox* box = toLayoutBox(layoutObject);
     ASSERT_TRUE(box->usesCompositedScrolling());
     CompositedLayerMapping* compositedLayerMapping = box->layer()->compositedLayerMapping();
     ASSERT_TRUE(compositedLayerMapping->hasScrollingLayer());
     DCHECK(compositedLayerMapping->scrollingContentsLayer());
     WebLayer* webScrollLayer = compositedLayerMapping->scrollingContentsLayer()->platformLayer();
     ASSERT_TRUE(webScrollLayer);
     ASSERT_NEAR(1.2, webScrollLayer->scrollPositionDouble().x, 0.01);
     ASSERT_NEAR(1.2, webScrollLayer->scrollPositionDouble().y, 0.01);
+
+    RuntimeEnabledFeatures::setFractionalScrollOffsetsEnabled(origFractionalOffsetsEnabled);
 }
 
 static WebLayer* webLayerFromElement(Element* element)
 {
     if (!element)
         return 0;
     LayoutObject* layoutObject = element->layoutObject();
     if (!layoutObject || !layoutObject->isBoxModelObject())
         return 0;
     PaintLayer* layer = toLayoutBoxModelObject(layoutObject)->layer();
@@ skipping 429 matching lines @@
     EXPECT_FALSE(scrollLayer->shouldScrollOnMainThread());
 
     fixedPos->setInlineStyleProperty(CSSPropertyTransform, CSSValueNone);
     forceFullCompositingUpdate();
 
     EXPECT_FALSE(static_cast<LayoutBoxModelObject*>(fixedPos->layoutObject())->layer()->hasCompositedLayerMapping());
     EXPECT_TRUE(scrollLayer->shouldScrollOnMainThread());
 }
 
 } // namespace blink