Communicate MT changes to impl-only scroll offset animations

third_party/WebKit/Source/platform/animation/CompositorAnimationHost.h

Index: third_party/WebKit/Source/platform/animation/CompositorAnimationHost.h
diff --git a/third_party/WebKit/Source/platform/animation/CompositorAnimationHost.h b/third_party/WebKit/Source/platform/animation/CompositorAnimationHost.h
new file mode 100644
index 0000000000000000000000000000000000000000..97795df956f3788c655420fcb48103e0b96b0501
--- /dev/null
+++ b/third_party/WebKit/Source/platform/animation/CompositorAnimationHost.h
@@ -0,0 +1,41 @@
+// 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 CompositorAnimationHost_h
+#define CompositorAnimationHost_h
+
+#include "base/memory/ref_counted.h"
+#include "cc/animation/animation_host.h"
+#include "platform/PlatformExport.h"
+#include "ui/gfx/geometry/vector2d.h"
+#include "wtf/Noncopyable.h"
+
+#include <memory>
+
+namespace cc {
+struct ScrollOffsetAnimationUpdate;
+}
+
+namespace blink {
+
+// A compositor representation for cc::AnimationHost.
+// This class wraps cc::AnimationHost and is currently only created from
+// CompositorAnimationTimeline::compositorAnimationHost.
+// TODO(ymalik): Correctly introduce CompositorAnimationHost to blink. See
+// crbug.com/610763.
+class PLATFORM_EXPORT CompositorAnimationHost {
+public:
+    explicit CompositorAnimationHost(cc::AnimationHost*);
+
+    cc::AnimationHost* animationHost() const;

[loyso (OOO), 2016/05/13 01:27:09]

It exposes cc guts. It this accessor used in testing only?

[ymalik, 2016/05/13 03:11:03]

Yes. CompositorAnimationTimeline also exposes cc::AnimationTimeline, but perhaps
thats not preferred? Do you suggest getting rid of it and adding the test as a
friend for testing?

+
+    void updateImplOnlyScrollOffsetAnimation(const gfx::Vector2dF& adjustment, cc::ElementId);
+
+private:
+    cc::AnimationHost* m_animationHost;
+};
+
+} // namespace blink
+
+#endif // CompositorAnimationTimeline_h