Run the later parts of startup as UI thread tasks

content/common/startup_task_runner_unittest.cc

+// Copyright (c) 2013 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 "content/public/common/startup_task_runner.h"
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/location.h"
+#include "base/run_loop.h"
+#include "base/task_runner.h"
+
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+namespace {
+
+using base::Closure;
+using testing::_;
+using testing::Assign;
+using testing::Invoke;
+using testing::WithArg;
+
+class StartupTaskRunnerTest : public testing::Test {
+ private:
+
+  int last_task_;
+
+ public:
+
+  virtual void SetUp() { last_task_ = 0; }
+
+  void Task1() { last_task_ = 1; }
+
+  void Task2() { last_task_ = 2; }
+
+  int GetLastTask() { return last_task_; }
+};
+
+class MockObserver : public StartupTaskRunner::Observer {
+ public:
+  MOCK_METHOD0(AllStartupTasksRan, void());
+};
+
+// We can't use the real message loop, even if we want to, since doing so on
+// Android requires a complex Java infrastructure. The test would have to built
+// as a content_shell test; but content_shell startup invokes the class we are
+// trying to test.
+//
+// The mocks are not directly in TaskRunnerProxy because reference counted
+// objects seem to confuse the mocking framework
+
+class MockTaskRunner {
+ public:
+  MOCK_METHOD3(
+      PostDelayedTask,
+      bool(const tracked_objects::Location&, const Closure&, base::TimeDelta));
+  MOCK_METHOD3(
+      PostNonNestableDelayedTask,
+      bool(const tracked_objects::Location&, const Closure&, base::TimeDelta));
+};
+
+class TaskRunnerProxy : public base::SingleThreadTaskRunner {
+ public:
+  TaskRunnerProxy(MockTaskRunner* mock) : mock_(mock) {}
+  bool RunsTasksOnCurrentThread() const { return true; }
+  bool PostDelayedTask(const tracked_objects::Location& location,
+                       const Closure& closure,
+                       base::TimeDelta delta) {
+    return mock_->PostDelayedTask(location, closure, delta);
+  }
+  bool PostNonNestableDelayedTask(const tracked_objects::Location& location,
+                                  const Closure& closure,
+                                  base::TimeDelta delta) {
+    return mock_->PostNonNestableDelayedTask(location, closure, delta);
+  }
+
+ private:
+  MockTaskRunner* mock_;
+};
+
+TEST_F(StartupTaskRunnerTest, ImmediateExecution) {
+
+  MockTaskRunner mock_runner;
+  scoped_refptr<TaskRunnerProxy> proxy = new TaskRunnerProxy(&mock_runner);
+
+  EXPECT_CALL(mock_runner, PostDelayedTask(_, _, _)).Times(0);
+  EXPECT_CALL(mock_runner, PostNonNestableDelayedTask(_, _, _)).Times(0);
+
+  scoped_refptr<StartupTaskRunner> runner =
+      new StartupTaskRunner(StartupTaskRunner::IMMEDIATE, NULL);
+
+  runner->SetProxy(proxy);
+
+  base::Closure task1 =
+      base::Bind(&StartupTaskRunnerTest::Task1, base::Unretained(this));
+  runner->AddTask(task1);
+  EXPECT_EQ(GetLastTask(), 0);
+  base::Closure task2 =
+      base::Bind(&StartupTaskRunnerTest::Task2, base::Unretained(this));
+  runner->AddTask(task2);
+
+  // Nothing should run until we tell them to.
+  EXPECT_EQ(GetLastTask(), 0);
+  runner->StartRunningTasks();
+
+  // On an immediate StartupTaskRunner the tasks should now all have run.
+  EXPECT_EQ(GetLastTask(), 2);
+}
+
+TEST_F(StartupTaskRunnerTest, ImmediateExecutionObserved) {
+  MockTaskRunner mock_runner;
+  scoped_refptr<TaskRunnerProxy> proxy = new TaskRunnerProxy(&mock_runner);
+
+  MockObserver observer;
+  EXPECT_CALL(observer, AllStartupTasksRan()).Times(1);
+
+  EXPECT_CALL(mock_runner, PostDelayedTask(_, _, _)).Times(0);
+  EXPECT_CALL(mock_runner, PostNonNestableDelayedTask(_, _, _)).Times(0);
+
+  scoped_refptr<StartupTaskRunner> runner =
+      new StartupTaskRunner(StartupTaskRunner::IMMEDIATE, &observer);
+
+  runner->SetProxy(proxy);
+
+  base::Closure task1 =
+      base::Bind(&StartupTaskRunnerTest::Task1, base::Unretained(this));
+  runner->AddTask(task1);
+  EXPECT_EQ(GetLastTask(), 0);
+  base::Closure task2 =
+      base::Bind(&StartupTaskRunnerTest::Task2, base::Unretained(this));
+  runner->AddTask(task2);
+
+  // Nothing should run until we tell them to.
+  EXPECT_EQ(GetLastTask(), 0);
+  runner->StartRunningTasks();
+
+  // On an immediate StartupTaskRunner the tasks should now all have run.
+  EXPECT_EQ(GetLastTask(), 2);
+}
+
+base::Closure task;
+
+// I couldn't get gMock's SaveArg to compile, hence had to save the argument
+// this way
+bool SaveTaskArg(const Closure& arg) {
+  task = arg;
+  return true;
+}
+
+TEST_F(StartupTaskRunnerTest, IncrementalExecution) {
+
+  MockTaskRunner mock_runner;
+  scoped_refptr<TaskRunnerProxy> proxy = new TaskRunnerProxy(&mock_runner);
+
+  bool done = false;
+  ;
+
+  MockObserver observer;
+
+  EXPECT_CALL(observer, AllStartupTasksRan()).WillOnce(Assign(&done, true));
+  EXPECT_CALL(mock_runner, PostDelayedTask(_, _, _)).Times(0);
+  EXPECT_CALL(
+      mock_runner,
+      PostNonNestableDelayedTask(_, _, base::TimeDelta::FromMilliseconds(0)))
+      .Times(3).WillRepeatedly(WithArg<1>(Invoke(SaveTaskArg)));
+
+  scoped_refptr<StartupTaskRunner> runner =
+      new StartupTaskRunner(StartupTaskRunner::INCREMENTAL, &observer);
+
+  runner->SetProxy(proxy);
+
+  base::Closure task1 =
+      base::Bind(&StartupTaskRunnerTest::Task1, base::Unretained(this));
+  runner->AddTask(task1);
+  base::Closure task2 =
+      base::Bind(&StartupTaskRunnerTest::Task2, base::Unretained(this));
+  runner->AddTask(task2);
+
+  // Nothing should run until we tell them to.
+  EXPECT_EQ(GetLastTask(), 0);
+  runner->StartRunningTasks();
+
+  // No tasks should have run yet, since we the message loop hasn't run.
+  EXPECT_EQ(GetLastTask(), 0);
+
+  // Fake the actual message loop. Each time a task is run a new task should
+  // be added to the queue, hence updating "task". The loop should actually run
+  // three times, the "4" is a backstop.
+  for (int i = 0; i < 4 && !done; i++) {
+    task.Run();
+    if (!done) {
+      EXPECT_EQ(i + 1, GetLastTask());
+    }
+  }
+}
+
+}  // namespace
+}  // namespace content