adjust new DL sources for recent removal of Fuchsia legacy code

Author: flar

flow/layers/display_list_layer.cc

@@ -87,10 +87,6 @@ void DisplayListLayer::Preroll(PrerollContext* context,
                                const SkMatrix& matrix) {
   TRACE_EVENT0("flutter", "DisplayListLayer::Preroll");
 
-#if defined(LEGACY_FUCHSIA_EMBEDDER)
-  CheckForChildLayerBelow(context);
-#endif
-
   DisplayList* disp_list = display_list();
 
   if (auto* cache = context->raster_cache) {

flow/layers/display_list_layer_unittests.cc

@@ -47,7 +47,6 @@ TEST_F(DisplayListLayerTest, PaintingEmptyLayerDies) {
   layer->Preroll(preroll_context(), SkMatrix());
   EXPECT_EQ(layer->paint_bounds(), SkRect::MakeEmpty());
   EXPECT_FALSE(layer->needs_painting(paint_context()));
-  EXPECT_FALSE(layer->needs_system_composite());
 
   EXPECT_DEATH_IF_SUPPORTED(layer->Paint(paint_context()),
                             "needs_painting\\(context\\)");
@@ -79,7 +78,6 @@ TEST_F(DisplayListLayerTest, SimpleDisplayList) {
             picture_bounds.makeOffset(layer_offset.fX, layer_offset.fY));
   EXPECT_EQ(layer->display_list(), display_list.get());
   EXPECT_TRUE(layer->needs_painting(paint_context()));
-  EXPECT_FALSE(layer->needs_system_composite());
 
   layer->Paint(paint_context());
   auto expected_draw_calls = std::vector(