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

cc/test/layer_internals_for_test.h

Index: cc/test/layer_internals_for_test.h
diff --git a/cc/test/layer_internals_for_test.h b/cc/test/layer_internals_for_test.h
new file mode 100644
index 0000000000000000000000000000000000000000..58fce8c9fd201267a2bc32bd333df33df4e58e85
--- /dev/null
+++ b/cc/test/layer_internals_for_test.h
@@ -0,0 +1,28 @@
+// 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_TEST_LAYER_INTERNALS_FOR_TEST_H_
+#define CC_TEST_LAYER_INTERNALS_FOR_TEST_H_
+
+#include "base/macros.h"
+#include "cc/layers/layer.h"
+
+namespace cc {
+
+// Utility class to give tests access to Layer private methods.
+class LayerInternalsForTest {
+ public:
+  explicit LayerInternalsForTest(Layer* layer);
+
+  void OnOpacityAnimated(float opacity);
+  void OnTransformAnimated(const gfx::Transform& transform);
+  void OnScrollOffsetAnimated(const gfx::ScrollOffset& scroll_offset);
+
+ private:
+  Layer* layer_;
+};
+
+}  // namespace cc
+
+#endif  // CC_TEST_LAYER_INTERNALS_FOR_TEST_H_