Add WebTaskRunner::postCancellableTask

third_party/WebKit/Source/platform/WebTaskRunnerTest.cpp

+// 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 "public/platform/WebTaskRunner.h"
+
+#include "platform/scheduler/test/fake_web_task_runner.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+namespace {
+
+void increment(int* x) {
+  ++*x;
+}
+
+void getIsActive(bool* isActive, RefPtr<TaskHandle>* handle) {
+  *isActive = (*handle)->isActive();
+}
+
+}  // namespace
+
+TEST(WebTaskRunnerTest, PostCancellableTaskTest) {
+  scheduler::FakeWebTaskRunner taskRunner;
+
+  // Run without cancellation.
+  int count = 0;
+  RefPtr<TaskHandle> handle = taskRunner.postCancellableTask(
+      BLINK_FROM_HERE, WTF::bind(&increment, WTF::unretained(&count)));
+  EXPECT_EQ(0, count);
+  EXPECT_TRUE(handle->isActive());
+  taskRunner.runUntilIdle();
+  EXPECT_EQ(1, count);
+  EXPECT_FALSE(handle->isActive());
+
+  count = 0;
+  handle = taskRunner.postDelayedCancellableTask(
+      BLINK_FROM_HERE, WTF::bind(&increment, WTF::unretained(&count)), 1);
+  EXPECT_EQ(0, count);
+  EXPECT_TRUE(handle->isActive());
+  taskRunner.runUntilIdle();
+  EXPECT_EQ(1, count);
+  EXPECT_FALSE(handle->isActive());
+
+  // Cancel a task.
+  count = 0;
+  handle = taskRunner.postCancellableTask(
+      BLINK_FROM_HERE, WTF::bind(&increment, WTF::unretained(&count)));
+  handle->cancel();
+  EXPECT_EQ(0, count);
+  EXPECT_FALSE(handle->isActive());
+  taskRunner.runUntilIdle();
+  EXPECT_EQ(0, count);
+
+  // The task should be valid even when the handle is dropped.
+  count = 0;
+  handle = taskRunner.postCancellableTask(
+      BLINK_FROM_HERE, WTF::bind(&increment, WTF::unretained(&count)));
+  EXPECT_TRUE(handle->isActive());
+  handle = nullptr;
+  EXPECT_EQ(0, count);
+  taskRunner.runUntilIdle();
+  EXPECT_EQ(1, count);
+
+  // handle->isActive() should switch to false before the task starts running.
+  bool isActive = false;
+  handle = taskRunner.postCancellableTask(
+      BLINK_FROM_HERE, WTF::bind(&getIsActive, WTF::unretained(&isActive),
+                                 WTF::unretained(&handle)));
+  EXPECT_TRUE(handle->isActive());
+  taskRunner.runUntilIdle();
+  EXPECT_FALSE(isActive);
+  EXPECT_FALSE(handle->isActive());
+}
+
+}  // namespace blink