Enable webkit_compositor_unittests

cc/CCLayerTreeHostImplTest.cpp

Index: cc/CCLayerTreeHostImplTest.cpp
diff --git a/cc/CCLayerTreeHostImplTest.cpp b/cc/CCLayerTreeHostImplTest.cpp
index a8c346aeeba4fbad15d843ae2a47ad0587ee2bde..bad57821197b53a9b0e5fe941754460dccc16855 100644
--- a/cc/CCLayerTreeHostImplTest.cpp
+++ b/cc/CCLayerTreeHostImplTest.cpp
@@ -380,6 +380,24 @@ TEST_F(CCLayerTreeHostImplTest, nonFastScrollableRegionWithOffset)
     EXPECT_EQ(m_hostImpl->scrollBegin(IntPoint(10, 10), CCInputHandlerClient::Wheel), CCInputHandlerClient::ScrollOnMainThread);
 }
 
+TEST_F(CCLayerTreeHostImplTest, maxScrollPositionChangedByDeviceScaleFactor)
+{
+    setupScrollAndContentsLayers(IntSize(100, 100));
+
+    float deviceScaleFactor = 2;
+    IntSize layoutViewport(25, 25);
+    IntSize deviceViewport(layoutViewport);
+    deviceViewport.scale(deviceScaleFactor);
+    m_hostImpl->setViewportSize(layoutViewport, deviceViewport);
+    m_hostImpl->setDeviceScaleFactor(deviceScaleFactor);
+    EXPECT_EQ(m_hostImpl->rootLayer()->maxScrollPosition(), IntSize(25, 25));
+
+    deviceScaleFactor = 1;
+    m_hostImpl->setViewportSize(layoutViewport, layoutViewport);
+    m_hostImpl->setDeviceScaleFactor(deviceScaleFactor);
+    EXPECT_EQ(m_hostImpl->rootLayer()->maxScrollPosition(), IntSize(75, 75));
+}
+
 TEST_F(CCLayerTreeHostImplTest, pinchGesture)
 {
     setupScrollAndContentsLayers(IntSize(100, 100));