Adds a CancellableTaskFactory and exposes postLoadingTasks to Blink

Source/platform/scheduler/CancellableTaskFactoryTest.cpp

Index: Source/platform/scheduler/CancellableTaskFactoryTest.cpp
diff --git a/Source/platform/scheduler/CancellableTaskFactoryTest.cpp b/Source/platform/scheduler/CancellableTaskFactoryTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..c6c25a4b1446e9ff9563f63cb5394b4841973342
--- /dev/null
+++ b/Source/platform/scheduler/CancellableTaskFactoryTest.cpp
@@ -0,0 +1,131 @@
+// 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.
+
+#include "config.h"
+#include "platform/scheduler/CancellableTaskFactory.h"
+
+#include <gtest/gtest.h>
+
+using blink::CancellableTaskFactory;
+using blink::WebThread;
+
+namespace {
+
+typedef testing::Test CancellableTaskFactoryTest;
+
+TEST_F(CancellableTaskFactoryTest, IsPending_TaskNotCreated)
+{
+    CancellableTaskFactory factory(nullptr);
+
+    EXPECT_FALSE(factory.isPending());
+}
+
+TEST_F(CancellableTaskFactoryTest, IsPending_TaskCreated)
+{
+    CancellableTaskFactory factory(nullptr);
+    OwnPtr<WebThread::Task> task = adoptPtr(factory.task());
+
+    EXPECT_TRUE(factory.isPending());
+}
+
+void EmptyFn()
+{
+}
+
+TEST_F(CancellableTaskFactoryTest, IsPending_TaskCreatedAndRun)
+{
+    CancellableTaskFactory factory(WTF::bind(&EmptyFn));
+    {
+        OwnPtr<WebThread::Task> task = adoptPtr(factory.task());
+        task->run();
+    }
+
+    EXPECT_FALSE(factory.isPending());
+}
+
+TEST_F(CancellableTaskFactoryTest, IsPending_TaskCreatedAndDestroyed)
+{
+    CancellableTaskFactory factory(nullptr);
+    delete factory.task();
+
+    EXPECT_FALSE(factory.isPending());
+}
+
+TEST_F(CancellableTaskFactoryTest, IsPending_TaskCreatedAndCancelled)
+{
+    CancellableTaskFactory factory(nullptr);
+    OwnPtr<WebThread::Task> task = adoptPtr(factory.task());
+    factory.cancel();
+
+    EXPECT_FALSE(factory.isPending());
+}
+
+void AddOne(int* ptr)
+{
+    *ptr += 1;
+}
+
+TEST_F(CancellableTaskFactoryTest, Run_ClosureIsExecuted)
+{
+    int executionCount = 0;
+    CancellableTaskFactory factory(WTF::bind(&AddOne, &executionCount));
+    OwnPtr<WebThread::Task> task = adoptPtr(factory.task());
+    task->run();
+
+    EXPECT_EQ(1, executionCount);
+}
+
+TEST_F(CancellableTaskFactoryTest, Run_ClosureIsExecutedOnlyOnce)
+{
+    int executionCount = 0;
+    CancellableTaskFactory factory(WTF::bind(&AddOne, &executionCount));
+    OwnPtr<WebThread::Task> task = adoptPtr(factory.task());
+    task->run();
+    task->run();
+    task->run();
+    task->run();
+
+    EXPECT_EQ(1, executionCount);
+}
+
+TEST_F(CancellableTaskFactoryTest, Run_FactoryDestructionPreventsExecution)
+{
+    int executionCount = 0;
+    OwnPtr<WebThread::Task> task;
+    {
+        CancellableTaskFactory factory(WTF::bind(&AddOne, &executionCount));
+        task = adoptPtr(factory.task());
+    }
+    task->run();
+
+    EXPECT_EQ(0, executionCount);
+}
+
+TEST_F(CancellableTaskFactoryTest, Cancel)
+{
+    int executionCount = 0;
+    CancellableTaskFactory factory(WTF::bind(&AddOne, &executionCount));
+    OwnPtr<WebThread::Task> task = adoptPtr(factory.task());
+    factory.cancel();
+    task->run();
+
+    EXPECT_EQ(0, executionCount);
+}
+
+TEST_F(CancellableTaskFactoryTest, CreatingANewTaskCancelsPreviousOnes)
+{
+    int executionCount = 0;
+    CancellableTaskFactory factory(WTF::bind(&AddOne, &executionCount));
+
+    OwnPtr<WebThread::Task> taskA = adoptPtr(factory.task());
+    OwnPtr<WebThread::Task> taskB = adoptPtr(factory.task());
+
+    taskA->run();
+    EXPECT_EQ(0, executionCount);
+
+    taskB->run();
+    EXPECT_EQ(1, executionCount);
+}
+
+} // namespace