cc: Add SwapPromiseManager and SurfaceSequenceGenerator.

cc/trees/swap_promise_manager.h

+// 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_TREES_SWAP_PROMISE_MANAGER_H_
+#define CC_TREES_SWAP_PROMISE_MANAGER_H_
+
+#include <set>
+#include <vector>
+
+#include "base/macros.h"
+#include "cc/base/cc_export.h"
+#include "cc/output/swap_promise.h"
+
+namespace cc {
+class SwapPromise;
+class SwapPromiseMonitor;
+
+class CC_EXPORT SwapPromiseManager {
+ public:
+  SwapPromiseManager();
+  ~SwapPromiseManager();
+
+  // Call this function when you expect there to be a swap buffer.
+  // See swap_promise.h for how to use SwapPromise.
+  void QueueSwapPromise(std::unique_ptr<SwapPromise> swap_promise);
+
+  // When a SwapPromiseMonitor is created on the main thread, it calls
+  // InsertSwapPromiseMonitor() to register itself with LayerTreeHost.
+  // When the monitor is destroyed, it calls RemoveSwapPromiseMonitor()
+  // to unregister itself.
+  void InsertSwapPromiseMonitor(SwapPromiseMonitor* monitor);
+  void RemoveSwapPromiseMonitor(SwapPromiseMonitor* monitor);
+
+  // Called when a commit request is made on the LayerTreeHost.
+  void NotifySwapPromiseMonitorsOfSetNeedsCommit();
+
+  // Called before the commit of the main thread state will be started.
+  void WillCommit();
+
+  // The current swap promise list is moved to the caller.
+  std::vector<std::unique_ptr<SwapPromise>> TakeSwapPromises();
+
+  // Breaks the currently queued swap promises with the specified reason.
+  void BreakSwapPromises(SwapPromise::DidNotSwapReason reason);
+
+  size_t num_queued_swap_promises() const { return swap_promise_list_.size(); }
+
+ private:
+  std::vector<std::unique_ptr<SwapPromise>> swap_promise_list_;
+  std::set<SwapPromiseMonitor*> swap_promise_monitors_;
+
+  DISALLOW_COPY_AND_ASSIGN(SwapPromiseManager);
+};
+
+}  // namespace cc
+
+#endif  // CC_TREES_SWAP_PROMISE_MANAGER_H_