compositor-worker: cc->blink mutation plumbing

cc/animation/layer_tree_mutator.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CC_ANIMATION_LAYER_TREE_MUTATOR_H_
+#define CC_ANIMATION_LAYER_TREE_MUTATOR_H_
+
+#include "base/callback_forward.h"
+
+namespace cc {
+
+class LayerTreeMutator {
+ public:
+  virtual ~LayerTreeMutator() {}
+
+  // The callback which is responsible for applying layer tree mutations to DOM
+  // elements.
+  using ApplyMutationsCallback = base::Closure;

[esprehn, 2016/03/31 05:03:11]

why add a typedef for this? Seems more clear to just use base::Closure to me. I
guess I defer to Dana. :)

[danakj, 2016/04/05 17:41:11]

Ya, just use a Closure IMO.

+  virtual ApplyMutationsCallback TakeMutations() = 0;
+};
+
+}  // namespace cc
+
+#endif  // CC_ANIMATION_LAYER_TREE_MUTATOR_H_