cc: Simplify task and its derived classes.

cc/raster/task.cc

+// 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.
+
+#include "cc/raster/task.h"
+
+#include "base/logging.h"
+
+namespace cc {
+
+Task::Task()
+    : did_schedule_(false),
+      did_complete_(false),
+      will_run_(false),
+      did_run_(false) {}
+
+Task::~Task() {
+  DCHECK(!did_schedule_);
+  DCHECK(!will_run_);
+  DCHECK(!did_run_ || did_complete_);
+}
+
+void Task::WillRun() {
+  DCHECK(!will_run_);
+  DCHECK(!did_run_);
+  will_run_ = true;
+}
+
+void Task::DidRun() {
+  DCHECK(will_run_);
+  will_run_ = false;
+  did_run_ = true;
+}
+
+bool Task::HasFinishedRunning() const {
+  return did_run_;
+}
+
+void Task::WillSchedule() {
+  DCHECK(!did_schedule_);
+}
+
+void Task::DidSchedule() {
+  did_schedule_ = true;
+  did_complete_ = false;
+}
+
+bool Task::HasBeenScheduled() const {
+  return did_schedule_;
+}
+
+void Task::WillComplete() {
+  DCHECK(!did_complete_);
+}
+
+void Task::DidComplete() {
+  DCHECK(did_schedule_);
+  DCHECK(!did_complete_);
+  did_schedule_ = false;
+  did_complete_ = true;
+}
+
+bool Task::HasCompleted() const {
+  return did_complete_;
+}
+
+}  // namespace cc