CC Animation: Use ElementId to attach CC animation players.

cc/test/layer_test_common.h

Index: cc/test/layer_test_common.h
diff --git a/cc/test/layer_test_common.h b/cc/test/layer_test_common.h
index 7c1a60085f2e0d27f7521c067de2fb28813e8d79..72d89ca551fdee7f41ce87703329bb2f87aa82c6 100644
--- a/cc/test/layer_test_common.h
+++ b/cc/test/layer_test_common.h
@@ -60,6 +60,7 @@ class LayerTestCommon {
     T* AddChildToRoot() {
       std::unique_ptr<T> layer =
           T::Create(host_->host_impl()->active_tree(), layer_impl_id_++);
+      layer->SetElementId(NextElementId());
       T* ptr = layer.get();
       root_layer()->AddChild(std::move(layer));
       return ptr;
@@ -69,6 +70,7 @@ class LayerTestCommon {
     T* AddChild(LayerImpl* parent) {
       std::unique_ptr<T> layer =
           T::Create(host_->host_impl()->active_tree(), layer_impl_id_++);
+      layer->SetElementId(NextElementId());
       T* ptr = layer.get();
       parent->AddChild(std::move(layer));
       return ptr;
@@ -78,6 +80,7 @@ class LayerTestCommon {
     T* AddReplicaLayer(LayerImpl* origin) {
       std::unique_ptr<T> layer =
           T::Create(host_->host_impl()->active_tree(), layer_impl_id_++);
+      layer->SetElementId(NextElementId());
       T* ptr = layer.get();
       origin->SetReplicaLayer(std::move(layer));
       return ptr;
@@ -87,6 +90,7 @@ class LayerTestCommon {
     T* AddChildToRoot(const A& a) {
       std::unique_ptr<T> layer =
           T::Create(host_->host_impl()->active_tree(), layer_impl_id_++, a);
+      layer->SetElementId(NextElementId());
       T* ptr = layer.get();
       root_layer()->AddChild(std::move(layer));
       return ptr;
@@ -96,6 +100,7 @@ class LayerTestCommon {
     T* AddChildToRoot(const A& a, const B& b) {
       std::unique_ptr<T> layer =
           T::Create(host_->host_impl()->active_tree(), layer_impl_id_++, a, b);
+      layer->SetElementId(NextElementId());
       T* ptr = layer.get();
       root_layer()->AddChild(std::move(layer));
       return ptr;
@@ -105,6 +110,7 @@ class LayerTestCommon {
     T* AddChildToRoot(const A& a, const B& b, const C& c, const D& d) {
       std::unique_ptr<T> layer = T::Create(host_->host_impl()->active_tree(),
                                            layer_impl_id_++, a, b, c, d);
+      layer->SetElementId(NextElementId());
       T* ptr = layer.get();
       root_layer()->AddChild(std::move(layer));
       return ptr;
@@ -123,6 +129,7 @@ class LayerTestCommon {
                       const E& e) {
       std::unique_ptr<T> layer = T::Create(host_->host_impl()->active_tree(),
                                            layer_impl_id_++, a, b, c, d, e);
+      layer->SetElementId(NextElementId());
       T* ptr = layer.get();
       root_layer()->AddChild(std::move(layer));
       return ptr;