cc: Add image decode queue functionality to image manager.

cc/test/fake_layer_tree_host.cc

Index: cc/test/fake_layer_tree_host.cc
diff --git a/cc/test/fake_layer_tree_host.cc b/cc/test/fake_layer_tree_host.cc
index acffdc50edc5e3d642ed0cc8829adfa72f8a3d93..a1f6f900dfafa128ab40b737e80549a648a931f2 100644
--- a/cc/test/fake_layer_tree_host.cc
+++ b/cc/test/fake_layer_tree_host.cc
@@ -75,6 +75,7 @@ std::unique_ptr<FakeLayerTreeHost> FakeLayerTreeHost::Create(
   params.settings = &settings;
   params.task_graph_runner = task_graph_runner;
   params.mutator_host = mutator_host;
+  params.image_worker_task_runner = nullptr;
   return base::WrapUnique(new FakeLayerTreeHost(client, &params, mode));
 }
 
@@ -91,6 +92,7 @@ std::unique_ptr<FakeLayerTreeHost> FakeLayerTreeHost::Create(
   params.task_graph_runner = task_graph_runner;
   params.image_serialization_processor = image_serialization_processor;
   params.mutator_host = mutator_host;
+  params.image_worker_task_runner = nullptr;
   return base::WrapUnique(new FakeLayerTreeHost(client, &params, mode));
 }