cc: Implement test task runner for tests.

cc/test/simple_task_runner.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_TEST_SIMPLE_TASK_RUNNER_H_
+#define CC_TEST_SIMPLE_TASK_RUNNER_H_
+
+#include "cc/raster/tile_task.h"
+
+namespace cc {
+
+// This task runner operates on single task. User has to call respective
+// functions to operate on task.
+class SimpleTaskRunner {

[vmpstr, 2016/05/20 23:23:19]

nit: can you rename this to something to indicate that it's a test? Any one of
the followings would work:

TestTileTaskRunner
FakeTileTaskRunner
TestTileTaskUtils

+ public:
+  // Schedules, runs and completes the task.
+  static void ProcessTask(TileTask* task);
+  static void ScheduleTask(TileTask* task);
+  static void CancelTask(TileTask* task);
+  // Before running the task it must be scheduled. Call ScheduleTask() before
+  // calling this function. This starts, runs and finishes the task.
+  static void RunTask(TileTask* task);
+  // Before completing the task it must be canceled or finished by running. Call
+  // RunTask() or CancelTask before calling this function.
+  static void CompleteTask(TileTask* task);
+};
+
+}  // namespace cc
+
+#endif  // CC_TEST_SIMPLE_TASK_RUNNER_H_