Communicate MT changes to impl-only scroll offset animations

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

Index: third_party/WebKit/Source/platform/animation/CompositorAnimationHost.cpp
diff --git a/third_party/WebKit/Source/platform/animation/CompositorAnimationHost.cpp b/third_party/WebKit/Source/platform/animation/CompositorAnimationHost.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..68f26a7c6e85717af0516a51bfe05500f23da965
--- /dev/null
+++ b/third_party/WebKit/Source/platform/animation/CompositorAnimationHost.cpp
@@ -0,0 +1,30 @@
+// 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 "platform/animation/CompositorAnimationHost.h"
+
+#include "cc/animation/animation_host.h"
+#include "cc/animation/scroll_offset_animations.h"
+
+namespace blink {
+
+CompositorAnimationHost::CompositorAnimationHost(cc::AnimationHost* host)
+    : m_animationHost(host) {}
+
+cc::AnimationHost* CompositorAnimationHost::animationHost() const
+{
+    return m_animationHost;
+}
+
+void CompositorAnimationHost::updateImplOnlyScrollOffsetAnimation(const gfx::Vector2dF& adjustment, int elementId)
+{
+    if (!m_animationHost)
+        return;
+
+    cc::ScrollOffsetAnimationUpdate update(cc::ScrollOffsetAnimationUpdate::Type::SCROLL_OFFSET_CHANGED, elementId);
+    update.adjustment_ = adjustment;
+    m_animationHost->scroll_offset_animations().AddUpdate(update);
+}
+
+} // namespace blink