Remove image_decode_tasks_enabled flag.

cc/layers/picture_layer_unittest.cc

Index: cc/layers/picture_layer_unittest.cc
diff --git a/cc/layers/picture_layer_unittest.cc b/cc/layers/picture_layer_unittest.cc
index 1ba4387702c4f6f3b52766c88c4ef043901696e5..7c784fb3b219582569f670f86458d35a94366557 100644
--- a/cc/layers/picture_layer_unittest.cc
+++ b/cc/layers/picture_layer_unittest.cc
@@ -102,7 +102,6 @@ TEST(PictureLayerTest, InvalidateRasterAfterUpdate) {
   std::unique_ptr<CompositorFrameSink> compositor_frame_sink(
       FakeCompositorFrameSink::Create3d());
   LayerTreeSettings layer_tree_settings = LayerTreeSettings();
-  layer_tree_settings.image_decode_tasks_enabled = true;
   FakeLayerTreeHostImpl host_impl(
       layer_tree_settings, &impl_task_runner_provider, &task_graph_runner);
   host_impl.SetVisible(true);
@@ -145,7 +144,6 @@ TEST(PictureLayerTest, InvalidateRasterWithoutUpdate) {
   std::unique_ptr<CompositorFrameSink> compositor_frame_sink(
       FakeCompositorFrameSink::Create3d());
   LayerTreeSettings layer_tree_settings = LayerTreeSettings();
-  layer_tree_settings.image_decode_tasks_enabled = true;
   FakeLayerTreeHostImpl host_impl(
       layer_tree_settings, &impl_task_runner_provider, &task_graph_runner);
   host_impl.SetVisible(true);
@@ -192,7 +190,6 @@ TEST(PictureLayerTest, ClearVisibleRectWhenNoTiling) {
   std::unique_ptr<CompositorFrameSink> compositor_frame_sink(
       FakeCompositorFrameSink::Create3d());
   LayerTreeSettings layer_tree_settings = LayerTreeSettings();
-  layer_tree_settings.image_decode_tasks_enabled = true;
   FakeLayerTreeHostImpl host_impl(
       layer_tree_settings, &impl_task_runner_provider, &task_graph_runner);
   host_impl.SetVisible(true);