Implement compositor thread VSync aligned event queue

ui/events/blink/event_with_callback.h

Index: ui/events/blink/event_with_callback.h
diff --git a/ui/events/blink/event_with_callback.h b/ui/events/blink/event_with_callback.h
new file mode 100644
index 0000000000000000000000000000000000000000..c6fd612caf9d6085d252e47ed43a09e32d985498
--- /dev/null
+++ b/ui/events/blink/event_with_callback.h
@@ -0,0 +1,66 @@
+// 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 UI_EVENTS_BLINK_EVENT_WITH_CALLBACK_H_
+#define UI_EVENTS_BLINK_EVENT_WITH_CALLBACK_H_
+
+#include <list>
+
+#include "ui/events/blink/input_handler_proxy.h"
+#include "ui/events/latency_info.h"
+
+namespace ui {
+
+namespace test {
+class InputHandlerProxyEventQueueTest;
+}
+
+class EventWithCallback {
+ public:
+  EventWithCallback(
+      ScopedWebInputEvent event,
+      const LatencyInfo& latency,
+      base::TimeTicks timestamp_now,
+      const InputHandlerProxy::EventDispositionCallback& callback);
+  ~EventWithCallback();
+
+  bool CanCoalesceWith(const EventWithCallback& other) const WARN_UNUSED_RESULT;
+  void CoalesceWith(EventWithCallback* other, base::TimeTicks timestamp_now);
+
+  void RunCallbacks(InputHandlerProxy::EventDisposition,
+                    const LatencyInfo& latency,
+                    std::unique_ptr<DidOverscrollParams>);
+
+  const blink::WebInputEvent& event() const { return *event_; }
+  const LatencyInfo latency_info() const { return latency_; }
+  base::TimeTicks creation_timestamp() const { return creation_timestamp_; }
+  base::TimeTicks last_coalesced_timestamp() const {
+    return last_coalesced_timestamp_;
+  }
+  size_t coalesced_count() const { return original_events_.size(); }
+
+ private:
+  friend class test::InputHandlerProxyEventQueueTest;
+  struct OriginalEventWithCallback {
+    OriginalEventWithCallback(
+        ScopedWebInputEvent event,
+        const InputHandlerProxy::EventDispositionCallback& callback);
+    ~OriginalEventWithCallback();
+    ScopedWebInputEvent event_;
+    InputHandlerProxy::EventDispositionCallback callback_;
+  };
+
+  void SetTickClockForTesting(std::unique_ptr<base::TickClock> tick_clock);
+
+  ScopedWebInputEvent event_;
+  LatencyInfo latency_;
+  std::list<OriginalEventWithCallback> original_events_;
+
+  base::TimeTicks creation_timestamp_;
+  base::TimeTicks last_coalesced_timestamp_;
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_BLINK_EVENT_WITH_CALLBACK_H_