Report expected task queueing time via UMA

components/scheduler/base/test_count_uses_time_source.h

+// Copyright 2015 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 COMPONENTS_SCHEDULER_BASE_TEST_COUNT_USES_TIME_SOURCE_H_
+#define COMPONENTS_SCHEDULER_BASE_TEST_COUNT_USES_TIME_SOURCE_H_
+
+#include "base/macros.h"
+#include "base/time/tick_clock.h"
+
+namespace scheduler {
+
+class TestCountUsesTimeSource : public base::TickClock {
+ public:
+  explicit TestCountUsesTimeSource();
+  ~TestCountUsesTimeSource() override;
+
+  base::TimeTicks NowTicks() override;
+  int now_calls_count() { return now_calls_count_; }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestCountUsesTimeSource);
+
+  int now_calls_count_;
+};
+
+}  // namespace scheduler
+
+#endif  // COMPONENTS_SCHEDULER_BASE_TEST_COUNT_USES_TIME_SOURCE_H_