Remove parts of //cc we aren't using

cc/trees/scoped_abort_remaining_swap_promises.h

-// Copyright 2014 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_TREES_SCOPED_ABORT_REMAINING_SWAP_PROMISES_H_
-#define CC_TREES_SCOPED_ABORT_REMAINING_SWAP_PROMISES_H_
-
-#include "cc/output/swap_promise.h"
-#include "cc/trees/layer_tree_host.h"
-
-namespace cc {
-
-class ScopedAbortRemainingSwapPromises {
- public:
-  explicit ScopedAbortRemainingSwapPromises(LayerTreeHost* layer_tree_host)
-      : layer_tree_host_(layer_tree_host) {}
-
-  ~ScopedAbortRemainingSwapPromises() {
-    layer_tree_host_->BreakSwapPromises(SwapPromise::COMMIT_FAILS);
-  }
-
- private:
-  LayerTreeHost* layer_tree_host_;
-
-  DISALLOW_COPY_AND_ASSIGN(ScopedAbortRemainingSwapPromises);
-};
-
-}  // namespace cc
-
-#endif  // CC_TREES_SCOPED_ABORT_REMAINING_SWAP_PROMISES_H_