cc: Set up the framework to restrict access to Layer internals.

cc/test/layer_internals_for_test.cc

+// 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.
+
+#include "cc/test/layer_internals_for_test.h"
+
+#include "cc/layers/layer.h"
+
+namespace cc {
+
+LayerInternalsForTest::LayerInternalsForTest(Layer* layer) : layer_(layer) {}
+
+void LayerInternalsForTest::OnOpacityAnimated(float opacity) {
+  layer_->OnOpacityAnimated(opacity);
+}
+
+void LayerInternalsForTest::OnTransformAnimated(
+    const gfx::Transform& transform) {
+  layer_->OnTransformAnimated(transform);
+}
+
+void LayerInternalsForTest::OnScrollOffsetAnimated(
+    const gfx::ScrollOffset& scroll_offset) {
+  layer_->OnScrollOffsetAnimated(scroll_offset);
+}
+
+}  // namespace cc