cc: Give non-drawing layers that are rasterized a lower priority.

cc/trees/layer_tree_host_impl_unittest.cc

Index: cc/trees/layer_tree_host_impl_unittest.cc
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index 3ad95e8494b3296dd320535fc083cb5094d0ced5..36fd48a131b020671953d54d4af33a2727a37c5a 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -12413,5 +12413,9 @@ TEST_F(LayerTreeHostImplTest, CheckerImagingTileInvalidation) {
   EXPECT_EQ(expected_invalidation, *(root->GetPendingInvalidation()));
 }
 
+TEST_F(LayerTreeHostImplTest, RasterTilePrioritizationForNonDrawingLayers) {
+  host_impl_->SetViewportSize(gfx::Size(500, 500));
+}
+
 }  // namespace
 }  // namespace cc