Pass accurate contentsScale to LayerImpl.

cc/tiled_layer_unittest.cc

Index: cc/tiled_layer_unittest.cc
diff --git a/cc/tiled_layer_unittest.cc b/cc/tiled_layer_unittest.cc
index d21911412bf897ddb050dfbfa46bac62b76cadd1..2b5e4bd5195230393a36cd38d861b3f94e1ea87a 100644
--- a/cc/tiled_layer_unittest.cc
+++ b/cc/tiled_layer_unittest.cc
@@ -1164,9 +1164,10 @@ TEST_F(TiledLayerTest, tilesPaintedWithOcclusionAndScaling)
     // a different layer space. In this case tiles are scaled to be 200x200
     // pixels, which means none should be occluded.
     layer->setContentsScale(0.5);
+    EXPECT_FLOAT_EQ(layer->contentsScaleX(), layer->contentsScaleY());
     layer->setBounds(IntSize(600, 600));
     WebTransformationMatrix drawTransform;
-    drawTransform.scale(1 / layer->contentsScale());
+    drawTransform.scale(1 / layer->contentsScaleX());
     layer->setDrawTransform(drawTransform);
     layer->setScreenSpaceTransform(drawTransform);