Add support for base::Closure in the MessageLoop.

base/message_loop_unittest.cc

 // Copyright (c) 2011 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 <vector>
 
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/compiler_specific.h"
 #include "base/eintr_wrapper.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/ref_counted.h"
-#include "base/task.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_WIN)
 #include "base/message_pump_win.h"
 #include "base/win/scoped_handle.h"
 #endif
 #if defined(OS_POSIX)
 #include "base/message_pump_libevent.h"
 #endif
 
 using base::PlatformThread;
 using base::Thread;
 using base::Time;
 using base::TimeDelta;
+using base::TimeTicks;
 
 // TODO(darin): Platform-specific MessageLoop tests should be grouped together
 // to avoid chopping this file up with so many #ifdefs.
 
 namespace {
 
 class MessageLoopTest : public testing::Test {};
 
 class Foo : public base::RefCounted<Foo> {
  public:
@@ skipping 35 matching lines @@
 
  private:
   friend class base::RefCounted<Foo>;
 
   ~Foo() {}
 
   int test_count_;
   std::string result_;
 };
 
-class QuitMsgLoop : public base::RefCounted<QuitMsgLoop> {
- public:
-  void QuitNow() {
-    MessageLoop::current()->Quit();
-  }
-
- private:
-  friend class base::RefCounted<QuitMsgLoop>;
-
-  ~QuitMsgLoop() {}
-};
-
+// TODO(ajwong): Remove this once we've finished getting rid of the PostTask()
+// compatibility methods.
 void RunTest_PostTask(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   // Add tests to message loop
   scoped_refptr<Foo> foo(new Foo());
   std::string a("a"), b("b"), c("c"), d("d");
   MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
       foo.get(), &Foo::Test0));
   MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
     foo.get(), &Foo::Test1ConstRef, a));
   MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
       foo.get(), &Foo::Test1Ptr, &b));
   MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
       foo.get(), &Foo::Test1Int, 100));
   MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
       foo.get(), &Foo::Test2Ptr, &a, &c));
   MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
     foo.get(), &Foo::Test2Mixed, a, &d));
 
   // After all tests, post a message that will shut down the message loop
-  scoped_refptr<QuitMsgLoop> quit(new QuitMsgLoop());
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      quit.get(), &QuitMsgLoop::QuitNow));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &MessageLoop::Quit, base::Unretained(MessageLoop::current())));
 
   // Now kick things off
   MessageLoop::current()->Run();
 
   EXPECT_EQ(foo->test_count(), 105);
   EXPECT_EQ(foo->result(), "abacad");
 }
 
-void RunTest_PostTask_SEH(MessageLoop::Type message_loop_type) {
+void RunTest_PostClosure(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   // Add tests to message loop
   scoped_refptr<Foo> foo(new Foo());
   std::string a("a"), b("b"), c("c"), d("d");
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      foo.get(), &Foo::Test0));
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      foo.get(), &Foo::Test1ConstRef, a));
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      foo.get(), &Foo::Test1Ptr, &b));
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      foo.get(), &Foo::Test1Int, 100));
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      foo.get(), &Foo::Test2Ptr, &a, &c));
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      foo.get(), &Foo::Test2Mixed, a, &d));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test0, foo.get()));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+    &Foo::Test1ConstRef, foo.get(), a));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test1Ptr, foo.get(), &b));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test1Int, foo.get(), 100));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test2Ptr, foo.get(), &a, &c));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test2Mixed, foo.get(), a, &d));
 
   // After all tests, post a message that will shut down the message loop
-  scoped_refptr<QuitMsgLoop> quit(new QuitMsgLoop());
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      quit.get(), &QuitMsgLoop::QuitNow));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &MessageLoop::Quit, base::Unretained(MessageLoop::current())));
+
+  // Now kick things off
+  MessageLoop::current()->Run();
+
+  EXPECT_EQ(foo->test_count(), 105);
+  EXPECT_EQ(foo->result(), "abacad");
+}
+
+void RunTest_PostClosure_SEH(MessageLoop::Type message_loop_type) {
+  MessageLoop loop(message_loop_type);
+
+  // Add tests to message loop
+  scoped_refptr<Foo> foo(new Foo());
+  std::string a("a"), b("b"), c("c"), d("d");
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test0, foo.get()));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test1ConstRef,foo.get(), a));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test1Ptr,foo.get(), &b));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test1Int,foo.get(), 100));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test2Ptr,foo.get(), &a, &c));
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &Foo::Test2Mixed,foo.get(), a, &d));
+
+  // After all tests, post a message that will shut down the message loop
+  MessageLoop::current()->PostClosure(FROM_HERE, base::Bind(
+      &MessageLoop::Quit, base::Unretained(MessageLoop::current())));
 
   // Now kick things off with the SEH block active.
   MessageLoop::current()->set_exception_restoration(true);
   MessageLoop::current()->Run();
   MessageLoop::current()->set_exception_restoration(false);
 
   EXPECT_EQ(foo->test_count(), 105);
   EXPECT_EQ(foo->result(), "abacad");
 }
 
-// This class runs slowly to simulate a large amount of work being done.
-class SlowTask : public Task {
- public:
-  SlowTask(int pause_ms, int* quit_counter)
-      : pause_ms_(pause_ms), quit_counter_(quit_counter) {
-  }
-  virtual void Run() {
-    PlatformThread::Sleep(pause_ms_);
-    if (--(*quit_counter_) == 0)
+// This function runs slowly to simulate a large amount of work being done.
+static void SlowFunc(int pause_ms, int* quit_counter) {
+    PlatformThread::Sleep(pause_ms);
+    if (--(*quit_counter) == 0)
       MessageLoop::current()->Quit();
-  }
- private:
-  int pause_ms_;
-  int* quit_counter_;
-};
+}
 
-// This class records the time when Run was called in a Time object, which is
+// This function records the time when Run was called in a Time object, which is
 // useful for building a variety of MessageLoop tests.
-class RecordRunTimeTask : public SlowTask {
- public:
-  RecordRunTimeTask(Time* run_time, int* quit_counter)
-      : SlowTask(10, quit_counter), run_time_(run_time) {
-  }
-  virtual void Run() {
-    *run_time_ = Time::Now();
+static void RecordRunTimeFunc(Time* run_time, int* quit_counter) {
+  *run_time = Time::Now();
+
     // Cause our Run function to take some time to execute.  As a result we can
-    // count on subsequent RecordRunTimeTask objects running at a future time,
+    // count on subsequent RecordRunTimeFunc()s running at a future time,
     // without worry about the resolution of our system clock being an issue.
-    SlowTask::Run();
-  }
- private:
-  Time* run_time_;
-};
+  SlowFunc(10, quit_counter);
+}
 
-void RunTest_PostDelayedTask_Basic(MessageLoop::Type message_loop_type) {
+void RunTest_PostDelayedClosure_Basic(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
-  // Test that PostDelayedTask results in a delayed task.
+  // Test that PostDelayedClosure results in a delayed task.
 
   const int kDelayMS = 100;
 
   int num_tasks = 1;
   Time run_time;
 
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time, &num_tasks), kDelayMS);
+  loop.PostDelayedClosure(
+      FROM_HERE, base::Bind(&RecordRunTimeFunc, &run_time, &num_tasks),
+      kDelayMS);
 
   Time time_before_run = Time::Now();
   loop.Run();
   Time time_after_run = Time::Now();
 
   EXPECT_EQ(0, num_tasks);
   EXPECT_LT(kDelayMS, (time_after_run - time_before_run).InMilliseconds());
 }
 
-void RunTest_PostDelayedTask_InDelayOrder(MessageLoop::Type message_loop_type) {
+void RunTest_PostDelayedClosure_InDelayOrder(
+    MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   // Test that two tasks with different delays run in the right order.
 
   int num_tasks = 2;
   Time run_time1, run_time2;
 
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time1, &num_tasks), 200);
+  loop.PostDelayedClosure(
+      FROM_HERE, base::Bind(&RecordRunTimeFunc, &run_time1, &num_tasks), 200);
   // If we get a large pause in execution (due to a context switch) here, this
   // test could fail.
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time2, &num_tasks), 10);
+  loop.PostDelayedClosure(
+      FROM_HERE, base::Bind(&RecordRunTimeFunc, &run_time2, &num_tasks), 10);
 
   loop.Run();
   EXPECT_EQ(0, num_tasks);
 
   EXPECT_TRUE(run_time2 < run_time1);
 }
 
-void RunTest_PostDelayedTask_InPostOrder(MessageLoop::Type message_loop_type) {
+void RunTest_PostDelayedClosure_InPostOrder(
+    MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   // Test that two tasks with the same delay run in the order in which they
   // were posted.
   //
   // NOTE: This is actually an approximate test since the API only takes a
   // "delay" parameter, so we are not exactly simulating two tasks that get
   // posted at the exact same time.  It would be nice if the API allowed us to
   // specify the desired run time.
 
   const int kDelayMS = 100;
 
   int num_tasks = 2;
   Time run_time1, run_time2;
 
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time1, &num_tasks), kDelayMS);
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time2, &num_tasks), kDelayMS);
+  loop.PostDelayedClosure(
+      FROM_HERE,
+      base::Bind(&RecordRunTimeFunc, &run_time1, &num_tasks),
+      kDelayMS);
+  loop.PostDelayedClosure(
+      FROM_HERE,
+      base::Bind(&RecordRunTimeFunc, &run_time2, &num_tasks),
+      kDelayMS);
 
   loop.Run();
   EXPECT_EQ(0, num_tasks);
 
   EXPECT_TRUE(run_time1 < run_time2);
 }
 
-void RunTest_PostDelayedTask_InPostOrder_2(
+void RunTest_PostDelayedClosure_InPostOrder_2(
     MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   // Test that a delayed task still runs after a normal tasks even if the
   // normal tasks take a long time to run.
 
   const int kPauseMS = 50;
 
   int num_tasks = 2;
   Time run_time;
 
-  loop.PostTask(
-      FROM_HERE, new SlowTask(kPauseMS, &num_tasks));
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time, &num_tasks), 10);
+  loop.PostClosure(
+      FROM_HERE, base::Bind(&SlowFunc, kPauseMS, &num_tasks));
+  loop.PostDelayedClosure(
+      FROM_HERE, base::Bind(&RecordRunTimeFunc, &run_time, &num_tasks), 10);
 
   Time time_before_run = Time::Now();
   loop.Run();
   Time time_after_run = Time::Now();
 
   EXPECT_EQ(0, num_tasks);
 
   EXPECT_LT(kPauseMS, (time_after_run - time_before_run).InMilliseconds());
 }
 
-void RunTest_PostDelayedTask_InPostOrder_3(
+void RunTest_PostDelayedClosure_InPostOrder_3(
     MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   // Test that a delayed task still runs after a pile of normal tasks.  The key
   // difference between this test and the previous one is that here we return
   // the MessageLoop a lot so we give the MessageLoop plenty of opportunities
   // to maybe run the delayed task.  It should know not to do so until the
   // delayed task's delay has passed.
 
   int num_tasks = 11;
   Time run_time1, run_time2;
 
   // Clutter the ML with tasks.
   for (int i = 1; i < num_tasks; ++i)
-    loop.PostTask(FROM_HERE, new RecordRunTimeTask(&run_time1, &num_tasks));
+    loop.PostClosure(FROM_HERE,
+                     base::Bind(&RecordRunTimeFunc, &run_time1, &num_tasks));
 
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time2, &num_tasks), 1);
+  loop.PostDelayedClosure(
+      FROM_HERE, base::Bind(&RecordRunTimeFunc, &run_time2, &num_tasks), 1);
 
   loop.Run();
   EXPECT_EQ(0, num_tasks);
 
   EXPECT_TRUE(run_time2 > run_time1);
 }
 
-void RunTest_PostDelayedTask_SharedTimer(MessageLoop::Type message_loop_type) {
+void RunTest_PostDelayedClosure_SharedTimer(
+    MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   // Test that the interval of the timer, used to run the next delayed task, is
   // set to a value corresponding to when the next delayed task should run.
 
   // By setting num_tasks to 1, we ensure that the first task to run causes the
   // run loop to exit.
   int num_tasks = 1;
   Time run_time1, run_time2;
 
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time1, &num_tasks), 1000000);
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time2, &num_tasks), 10);
+  loop.PostDelayedClosure(
+      FROM_HERE,
+      base::Bind(&RecordRunTimeFunc, &run_time1, &num_tasks),
+      1000000);
+  loop.PostDelayedClosure(
+      FROM_HERE, base::Bind(&RecordRunTimeFunc, &run_time2, &num_tasks), 10);
 
   Time start_time = Time::Now();
 
   loop.Run();
   EXPECT_EQ(0, num_tasks);
 
   // Ensure that we ran in far less time than the slower timer.
   TimeDelta total_time = Time::Now() - start_time;
   EXPECT_GT(5000, total_time.InMilliseconds());
 
   // In case both timers somehow run at nearly the same time, sleep a little
   // and then run all pending to force them both to have run.  This is just
   // encouraging flakiness if there is any.
   PlatformThread::Sleep(100);
   loop.RunAllPending();
 
   EXPECT_TRUE(run_time1.is_null());
   EXPECT_FALSE(run_time2.is_null());
 }
 
 #if defined(OS_WIN)
 
-class SubPumpTask : public Task {
- public:
-  virtual void Run() {
-    MessageLoop::current()->SetNestableTasksAllowed(true);
-    MSG msg;
-    while (GetMessage(&msg, NULL, 0, 0)) {
-      TranslateMessage(&msg);
-      DispatchMessage(&msg);
-    }
-    MessageLoop::current()->Quit();
+void SubPumpFunc() {
+  MessageLoop::current()->SetNestableTasksAllowed(true);
+  MSG msg;
+  while (GetMessage(&msg, NULL, 0, 0)) {
+    TranslateMessage(&msg);
+    DispatchMessage(&msg);
   }
-};
+  MessageLoop::current()->Quit();
+}
 
-class SubPumpQuitTask : public Task {
- public:
-  SubPumpQuitTask() {
-  }
-  virtual void Run() {
-    PostQuitMessage(0);
-  }
-};
-
-void RunTest_PostDelayedTask_SharedTimer_SubPump() {
+void RunTest_PostDelayedClosure_SharedTimer_SubPump() {
   MessageLoop loop(MessageLoop::TYPE_UI);
 
   // Test that the interval of the timer, used to run the next delayed task, is
   // set to a value corresponding to when the next delayed task should run.
 
   // By setting num_tasks to 1, we ensure that the first task to run causes the
   // run loop to exit.
   int num_tasks = 1;
   Time run_time;
 
-  loop.PostTask(FROM_HERE, new SubPumpTask());
+  loop.PostClosure(FROM_HERE, base::Bind(&SubPumpFunc));
 
   // This very delayed task should never run.
-  loop.PostDelayedTask(
-      FROM_HERE, new RecordRunTimeTask(&run_time, &num_tasks), 1000000);
+  loop.PostDelayedClosure(
+      FROM_HERE,
+      base::Bind(&RecordRunTimeFunc, &run_time, &num_tasks),
+      1000000);
 
-  // This slightly delayed task should run from within SubPumpTask::Run().
-  loop.PostDelayedTask(
-      FROM_HERE, new SubPumpQuitTask(), 10);
+  // This slightly delayed task should run from within SubPumpFunc).
+  loop.PostDelayedClosure(FROM_HERE, base::Bind(&PostQuitMessage, 0), 10);
 
   Time start_time = Time::Now();
 
   loop.Run();
   EXPECT_EQ(1, num_tasks);
 
   // Ensure that we ran in far less time than the slower timer.
   TimeDelta total_time = Time::Now() - start_time;
   EXPECT_GT(5000, total_time.InMilliseconds());
 
   // In case both timers somehow run at nearly the same time, sleep a little
   // and then run all pending to force them both to have run.  This is just
   // encouraging flakiness if there is any.
   PlatformThread::Sleep(100);
   loop.RunAllPending();
 
   EXPECT_TRUE(run_time.is_null());
 }
 
 #endif  // defined(OS_WIN)
 
-class RecordDeletionTask : public Task {
+class RecordDeletionProbe : public base::RefCounted<RecordDeletionProbe> {
  public:
-  RecordDeletionTask(Task* post_on_delete, bool* was_deleted)
+  RecordDeletionProbe(RecordDeletionProbe* post_on_delete, bool* was_deleted)
       : post_on_delete_(post_on_delete), was_deleted_(was_deleted) {
   }
-  ~RecordDeletionTask() {
+  ~RecordDeletionProbe() {
     *was_deleted_ = true;
     if (post_on_delete_)
-      MessageLoop::current()->PostTask(FROM_HERE, post_on_delete_);
+      MessageLoop::current()->PostClosure(
+          FROM_HERE,
+          base::Bind(&RecordDeletionProbe::Run, post_on_delete_.get()));
   }
   virtual void Run() {}
  private:
-  Task* post_on_delete_;
+  scoped_refptr<RecordDeletionProbe> post_on_delete_;
   bool* was_deleted_;
 };
 
-void RunTest_EnsureTaskDeletion(MessageLoop::Type message_loop_type) {
+void RunTest_EnsureDeletion(MessageLoop::Type message_loop_type) {
   bool a_was_deleted = false;
   bool b_was_deleted = false;
   {
     MessageLoop loop(message_loop_type);
-    loop.PostTask(
-        FROM_HERE, new RecordDeletionTask(NULL, &a_was_deleted));
-    loop.PostDelayedTask(
-        FROM_HERE, new RecordDeletionTask(NULL, &b_was_deleted), 1000);
+    loop.PostClosure(
+        FROM_HERE, base::Bind(&RecordDeletionProbe::Run,
+                              new RecordDeletionProbe(NULL, &a_was_deleted)));
+    loop.PostDelayedClosure(
+        FROM_HERE, base::Bind(&RecordDeletionProbe::Run,
+                              new RecordDeletionProbe(NULL, &b_was_deleted)),
+        1000);  // TODO(ajwong): Do we really need 1000ms here?
   }
   EXPECT_TRUE(a_was_deleted);
   EXPECT_TRUE(b_was_deleted);
 }
 
-void RunTest_EnsureTaskDeletion_Chain(MessageLoop::Type message_loop_type) {
+void RunTest_EnsureDeletion_Chain(MessageLoop::Type message_loop_type) {
   bool a_was_deleted = false;
   bool b_was_deleted = false;
   bool c_was_deleted = false;
   {
     MessageLoop loop(message_loop_type);
-    RecordDeletionTask* a = new RecordDeletionTask(NULL, &a_was_deleted);
-    RecordDeletionTask* b = new RecordDeletionTask(a, &b_was_deleted);
-    RecordDeletionTask* c = new RecordDeletionTask(b, &c_was_deleted);
-    loop.PostTask(FROM_HERE, c);
+    // The scoped_refptr for each of the below is held either by the chained
+    // RecordDeletionProbe, or the bound RecordDeletionProbe::Run() callback.
+    RecordDeletionProbe* a = new RecordDeletionProbe(NULL, &a_was_deleted);
+    RecordDeletionProbe* b = new RecordDeletionProbe(a, &b_was_deleted);
+    RecordDeletionProbe* c = new RecordDeletionProbe(b, &c_was_deleted);
+    loop.PostClosure(FROM_HERE, base::Bind(&RecordDeletionProbe::Run, c));
   }
   EXPECT_TRUE(a_was_deleted);
   EXPECT_TRUE(b_was_deleted);
   EXPECT_TRUE(c_was_deleted);
 }
 
-class NestingTest : public Task {
- public:
-  explicit NestingTest(int* depth) : depth_(depth) {
+void NestingFunc(int* depth) {
+  if (*depth > 0) {
+    *depth -= 1;
+    MessageLoop::current()->PostClosure(FROM_HERE,
+                                        base::Bind(&NestingFunc, depth));
+
+    MessageLoop::current()->SetNestableTasksAllowed(true);
+    MessageLoop::current()->Run();
   }
-  void Run() {
-    if (*depth_ > 0) {
-      *depth_ -= 1;
-      MessageLoop::current()->PostTask(FROM_HERE, new NestingTest(depth_));
-
-      MessageLoop::current()->SetNestableTasksAllowed(true);
-      MessageLoop::current()->Run();
-    }
-    MessageLoop::current()->Quit();
-  }
- private:
-  int* depth_;
-};
+  MessageLoop::current()->Quit();
+}
 
 #if defined(OS_WIN)
 
 LONG WINAPI BadExceptionHandler(EXCEPTION_POINTERS *ex_info) {
   ADD_FAILURE() << "bad exception handler";
   ::ExitProcess(ex_info->ExceptionRecord->ExceptionCode);
   return EXCEPTION_EXECUTE_HANDLER;
 }
 
 // This task throws an SEH exception: initially write to an invalid address.
 // If the right SEH filter is installed, it will fix the error.
-class CrasherTask : public Task {
+class Crasher : public base::RefCounted<Crasher> {
  public:
   // Ctor. If trash_SEH_handler is true, the task will override the unhandled
   // exception handler with one sure to crash this test.
-  explicit CrasherTask(bool trash_SEH_handler)
+  explicit Crasher(bool trash_SEH_handler)
       : trash_SEH_handler_(trash_SEH_handler) {
   }
+
   void Run() {
     PlatformThread::Sleep(1);
     if (trash_SEH_handler_)
       ::SetUnhandledExceptionFilter(&BadExceptionHandler);
     // Generate a SEH fault. We do it in asm to make sure we know how to undo
     // the damage.
 
 #if defined(_M_IX86)
 
     __asm {
-      mov eax, dword ptr [CrasherTask::bad_array_]
+      mov eax, dword ptr [Crasher::bad_array_]
       mov byte ptr [eax], 66
     }
 
 #elif defined(_M_X64)
 
     bad_array_[0] = 66;
 
 #else
 #error "needs architecture support"
 #endif
 
     MessageLoop::current()->Quit();
   }
   // Points the bad array to a valid memory location.
   static void FixError() {
     bad_array_ = &valid_store_;
   }
 
  private:
   bool trash_SEH_handler_;
   static volatile char* bad_array_;
   static char valid_store_;
 };
 
-volatile char* CrasherTask::bad_array_ = 0;
-char CrasherTask::valid_store_ = 0;
+volatile char* Crasher::bad_array_ = 0;
+char Crasher::valid_store_ = 0;
 
 // This SEH filter fixes the problem and retries execution. Fixing requires
-// that the last instruction: mov eax, [CrasherTask::bad_array_] to be retried
+// that the last instruction: mov eax, [Crasher::bad_array_] to be retried
 // so we move the instruction pointer 5 bytes back.
-LONG WINAPI HandleCrasherTaskException(EXCEPTION_POINTERS *ex_info) {
+LONG WINAPI HandleCrasherException(EXCEPTION_POINTERS *ex_info) {
   if (ex_info->ExceptionRecord->ExceptionCode != EXCEPTION_ACCESS_VIOLATION)
     return EXCEPTION_EXECUTE_HANDLER;
 
-  CrasherTask::FixError();
+  Crasher::FixError();
 
 #if defined(_M_IX86)
 
   ex_info->ContextRecord->Eip -= 5;
 
 #elif defined(_M_X64)
 
   ex_info->ContextRecord->Rip -= 5;
 
 #endif
 
   return EXCEPTION_CONTINUE_EXECUTION;
 }
 
 void RunTest_Crasher(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   if (::IsDebuggerPresent())
     return;
 
   LPTOP_LEVEL_EXCEPTION_FILTER old_SEH_filter =
-      ::SetUnhandledExceptionFilter(&HandleCrasherTaskException);
+      ::SetUnhandledExceptionFilter(&HandleCrasherException);
 
-  MessageLoop::current()->PostTask(FROM_HERE, new CrasherTask(false));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&Crasher::Run, new Crasher(false)));
   MessageLoop::current()->set_exception_restoration(true);
   MessageLoop::current()->Run();
   MessageLoop::current()->set_exception_restoration(false);
 
   ::SetUnhandledExceptionFilter(old_SEH_filter);
 }
 
 void RunTest_CrasherNasty(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   if (::IsDebuggerPresent())
     return;
 
   LPTOP_LEVEL_EXCEPTION_FILTER old_SEH_filter =
-      ::SetUnhandledExceptionFilter(&HandleCrasherTaskException);
+      ::SetUnhandledExceptionFilter(&HandleCrasherException);
 
-  MessageLoop::current()->PostTask(FROM_HERE, new CrasherTask(true));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&Crasher::Run, new Crasher(true)));
   MessageLoop::current()->set_exception_restoration(true);
   MessageLoop::current()->Run();
   MessageLoop::current()->set_exception_restoration(false);
 
   ::SetUnhandledExceptionFilter(old_SEH_filter);
 }
 
 #endif  // defined(OS_WIN)
 
 void RunTest_Nesting(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   int depth = 100;
-  MessageLoop::current()->PostTask(FROM_HERE, new NestingTest(&depth));
+  MessageLoop::current()->PostClosure(FROM_HERE,
+                                      base::Bind(&NestingFunc, &depth));
   MessageLoop::current()->Run();
   EXPECT_EQ(depth, 0);
 }
 
 const wchar_t* const kMessageBoxTitle = L"MessageLoop Unit Test";
 
 enum TaskType {
   MESSAGEBOX,
   ENDDIALOG,
   RECURSIVE,
@@ skipping 14 matching lines @@
 
   TaskType type;
   int cookie;
   bool start;
 
   bool operator == (const TaskItem& other) const {
     return type == other.type && cookie == other.cookie && start == other.start;
   }
 };
 
-typedef std::vector<TaskItem> TaskList;
-
 std::ostream& operator <<(std::ostream& os, TaskType type) {
   switch (type) {
   case MESSAGEBOX:        os << "MESSAGEBOX"; break;
   case ENDDIALOG:         os << "ENDDIALOG"; break;
   case RECURSIVE:         os << "RECURSIVE"; break;
   case TIMEDMESSAGELOOP:  os << "TIMEDMESSAGELOOP"; break;
   case QUITMESSAGELOOP:   os << "QUITMESSAGELOOP"; break;
   case ORDERERD:          os << "ORDERERD"; break;
   case PUMPS:             os << "PUMPS"; break;
   case SLEEP:             os << "SLEEP"; break;
   default:
     NOTREACHED();
     os << "Unknown TaskType";
     break;
   }
   return os;
 }
 
 std::ostream& operator <<(std::ostream& os, const TaskItem& item) {
   if (item.start)
     return os << item.type << " " << item.cookie << " starts";
   else
     return os << item.type << " " << item.cookie << " ends";
 }
 
-// Saves the order the tasks ran.
-class OrderedTasks : public Task {
+class TaskList {
  public:
-  OrderedTasks(TaskList* order, int cookie)
-      : order_(order),
-        type_(ORDERERD),
-        cookie_(cookie) {
-  }
-  OrderedTasks(TaskList* order, TaskType type, int cookie)
-      : order_(order),
-        type_(type),
-        cookie_(cookie) {
+  void RecordStart(TaskType type, int cookie) {
+    TaskItem item(type, cookie, true);
+    DVLOG(1) << item;
+    task_list_.push_back(item);
   }
 
-  void RunStart() {
-    TaskItem item(type_, cookie_, true);
+  void RecordEnd(TaskType type, int cookie) {
+    TaskItem item(type, cookie, false);
     DVLOG(1) << item;
-    order_->push_back(item);
-  }
-  void RunEnd() {
-    TaskItem item(type_, cookie_, false);
-    DVLOG(1) << item;
-    order_->push_back(item);
+    task_list_.push_back(item);
   }
 
-  virtual void Run() {
-    RunStart();
-    RunEnd();
+  size_t Size() {
+    return task_list_.size();
   }
 
- protected:
-  TaskList* order() const {
-    return order_;
-  }
-
-  int cookie() const {
-    return cookie_;
+  TaskItem Get(int n)  {
+    return task_list_[n];
   }
 
  private:
-  TaskList* order_;
-  TaskType type_;
-  int cookie_;
+  std::vector<TaskItem> task_list_;
 };
 
+// Saves the order the tasks ran.
+void OrderedFunc(TaskList* order, int cookie) {
+  order->RecordStart(ORDERERD, cookie);
+  order->RecordEnd(ORDERERD, cookie);
+}
+
 #if defined(OS_WIN)
 
 // MessageLoop implicitly start a "modal message loop". Modal dialog boxes,
 // common controls (like OpenFile) and StartDoc printing function can cause
 // implicit message loops.
-class MessageBoxTask : public OrderedTasks {
- public:
-  MessageBoxTask(TaskList* order, int cookie, bool is_reentrant)
-      : OrderedTasks(order, MESSAGEBOX, cookie),
-        is_reentrant_(is_reentrant) {
-  }
-
-  virtual void Run() {
-    RunStart();
-    if (is_reentrant_)
-      MessageLoop::current()->SetNestableTasksAllowed(true);
-    MessageBox(NULL, L"Please wait...", kMessageBoxTitle, MB_OK);
-    RunEnd();
-  }
-
- private:
-  bool is_reentrant_;
-};
+void MessageBoxFunc(TaskList* order, int cookie, bool is_reentrant) {
+  order->RecordStart(MESSAGEBOX, cookie);
+  if (is_reentrant)
+    MessageLoop::current()->SetNestableTasksAllowed(true);
+  MessageBox(NULL, L"Please wait...", kMessageBoxTitle, MB_OK);
+  order->RecordEnd(MESSAGEBOX, cookie);
+}
 
 // Will end the MessageBox.
-class EndDialogTask : public OrderedTasks {
- public:
-  EndDialogTask(TaskList* order, int cookie)
-      : OrderedTasks(order, ENDDIALOG, cookie) {
+void EndDialogFunc(TaskList* order, int cookie) {
+  order->RecordStart(ENDDIALOG, cookie);
+  HWND window = GetActiveWindow();
+  if (window != NULL) {
+    EXPECT_NE(EndDialog(window, IDCONTINUE), 0);
+    // Cheap way to signal that the window wasn't found if RunEnd() isn't
+    // called.
+    order->RecordEnd(ENDDIALOG, cookie);
   }
-
-  virtual void Run() {
-    RunStart();
-    HWND window = GetActiveWindow();
-    if (window != NULL) {
-      EXPECT_NE(EndDialog(window, IDCONTINUE), 0);
-      // Cheap way to signal that the window wasn't found if RunEnd() isn't
-      // called.
-      RunEnd();
-    }
-  }
-};
+}
 
 #endif  // defined(OS_WIN)
 
-class RecursiveTask : public OrderedTasks {
- public:
-  RecursiveTask(int depth, TaskList* order, int cookie, bool is_reentrant)
-      : OrderedTasks(order, RECURSIVE, cookie),
-        depth_(depth),
-        is_reentrant_(is_reentrant) {
+void RecursiveFunc(TaskList* order, int cookie, int depth,
+                   bool is_reentrant) {
+  order->RecordStart(RECURSIVE, cookie);
+  if (depth > 0) {
+    if (is_reentrant)
+      MessageLoop::current()->SetNestableTasksAllowed(true);
+    MessageLoop::current()->PostClosure(
+        FROM_HERE,
+        base::Bind(&RecursiveFunc, order, cookie, depth - 1, is_reentrant));
   }
+  order->RecordEnd(RECURSIVE, cookie);
+}
 
-  virtual void Run() {
-    RunStart();
-    if (depth_ > 0) {
-      if (is_reentrant_)
-        MessageLoop::current()->SetNestableTasksAllowed(true);
-      MessageLoop::current()->PostTask(FROM_HERE,
-          new RecursiveTask(depth_ - 1, order(), cookie(), is_reentrant_));
-    }
-    RunEnd();
-  }
+void RecursiveSlowFunc(TaskList* order, int cookie, int depth,
+                       bool is_reentrant) {
+  RecursiveFunc(order, cookie, depth, is_reentrant);
+  PlatformThread::Sleep(10);  // milliseconds
+}
 
- private:
-  int depth_;
-  bool is_reentrant_;
-};
+void QuitFunc(TaskList* order, int cookie) {
+  order->RecordStart(QUITMESSAGELOOP, cookie);
+  MessageLoop::current()->Quit();
+  order->RecordEnd(QUITMESSAGELOOP, cookie);
+}
 
-class RecursiveSlowTask : public RecursiveTask {
- public:
-  RecursiveSlowTask(int depth, TaskList* order, int cookie, bool is_reentrant)
-      : RecursiveTask(depth, order, cookie, is_reentrant) {
-  }
-
-  virtual void Run() {
-    RecursiveTask::Run();
-    PlatformThread::Sleep(10);  // milliseconds
-  }
-};
-
-class QuitTask : public OrderedTasks {
- public:
-  QuitTask(TaskList* order, int cookie)
-      : OrderedTasks(order, QUITMESSAGELOOP, cookie) {
-  }
-
-  virtual void Run() {
-    RunStart();
-    MessageLoop::current()->Quit();
-    RunEnd();
-  }
-};
-
-class SleepTask : public OrderedTasks {
- public:
-  SleepTask(TaskList* order, int cookie, int ms)
-      : OrderedTasks(order, SLEEP, cookie), ms_(ms) {
-  }
-
-  virtual void Run() {
-    RunStart();
-    PlatformThread::Sleep(ms_);
-    RunEnd();
-  }
-
- private:
-  int ms_;
-};
+void SleepFunc(TaskList* order, int cookie, int ms) {
+  order->RecordStart(SLEEP, cookie);
+  PlatformThread::Sleep(ms);
+  order->RecordEnd(SLEEP, cookie);
+}
 
 #if defined(OS_WIN)
+void RecursiveFuncWin(MessageLoop* target,
+                      HANDLE event,
+                      bool expect_window,
+                      TaskList* order,
+                      bool is_reentrant) {
+  target->PostClosure(FROM_HERE,
+                      base::Bind(&RecursiveFunc, order, 1, 2, is_reentrant));
+  target->PostClosure(FROM_HERE,
+                      base::Bind(&MessageBoxFunc, order, 2, is_reentrant));
+  target->PostClosure(FROM_HERE,
+                      base::Bind(&RecursiveFunc, order, 3, 2, is_reentrant));
+  // The trick here is that for recursive task processing, this task will be
+  // ran _inside_ the MessageBox message loop, dismissing the MessageBox
+  // without a chance.
+  // For non-recursive task processing, this will be executed _after_ the
+  // MessageBox will have been dismissed by the code below, where
+  // expect_window_ is true.
+  target->PostClosure(FROM_HERE,
+                      base::Bind(&EndDialogFunc, order, 4));
+  target->PostClosure(FROM_HERE,
+                      base::Bind(&QuitFunc, order, 5));
 
-class Recursive2Tasks : public Task {
- public:
-  Recursive2Tasks(MessageLoop* target,
-                  HANDLE event,
-                  bool expect_window,
-                  TaskList* order,
-                  bool is_reentrant)
-      : target_(target),
-        event_(event),
-        expect_window_(expect_window),
-        order_(order),
-        is_reentrant_(is_reentrant) {
-  }
+  // Enforce that every tasks are sent before starting to run the main thread
+  // message loop.
+  ASSERT_TRUE(SetEvent(event));
 
-  virtual void Run() {
-    target_->PostTask(FROM_HERE,
-                      new RecursiveTask(2, order_, 1, is_reentrant_));
-    target_->PostTask(FROM_HERE,
-                      new MessageBoxTask(order_, 2, is_reentrant_));
-    target_->PostTask(FROM_HERE,
-                      new RecursiveTask(2, order_, 3, is_reentrant_));
-    // The trick here is that for recursive task processing, this task will be
-    // ran _inside_ the MessageBox message loop, dismissing the MessageBox
-    // without a chance.
-    // For non-recursive task processing, this will be executed _after_ the
-    // MessageBox will have been dismissed by the code below, where
-    // expect_window_ is true.
-    target_->PostTask(FROM_HERE, new EndDialogTask(order_, 4));
-    target_->PostTask(FROM_HERE, new QuitTask(order_, 5));
-
-    // Enforce that every tasks are sent before starting to run the main thread
-    // message loop.
-    ASSERT_TRUE(SetEvent(event_));
-
-    // Poll for the MessageBox. Don't do this at home! At the speed we do it,
-    // you will never realize one MessageBox was shown.
-    for (; expect_window_;) {
-      HWND window = FindWindow(L"#32770", kMessageBoxTitle);
-      if (window) {
-        // Dismiss it.
-        for (;;) {
-          HWND button = FindWindowEx(window, NULL, L"Button", NULL);
-          if (button != NULL) {
-            EXPECT_EQ(0, SendMessage(button, WM_LBUTTONDOWN, 0, 0));
-            EXPECT_EQ(0, SendMessage(button, WM_LBUTTONUP, 0, 0));
-            break;
-          }
+  // Poll for the MessageBox. Don't do this at home! At the speed we do it,
+  // you will never realize one MessageBox was shown.
+  for (; expect_window;) {
+    HWND window = FindWindow(L"#32770", kMessageBoxTitle);
+    if (window) {
+      // Dismiss it.
+      for (;;) {
+        HWND button = FindWindowEx(window, NULL, L"Button", NULL);
+        if (button != NULL) {
+          EXPECT_EQ(0, SendMessage(button, WM_LBUTTONDOWN, 0, 0));
+          EXPECT_EQ(0, SendMessage(button, WM_LBUTTONUP, 0, 0));
+          break;
         }
-        break;
       }
+      break;
     }
   }
-
- private:
-  MessageLoop* target_;
-  HANDLE event_;
-  TaskList* order_;
-  bool expect_window_;
-  bool is_reentrant_;
-};
+}
 
 #endif  // defined(OS_WIN)
 
 void RunTest_RecursiveDenial1(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   EXPECT_TRUE(MessageLoop::current()->NestableTasksAllowed());
   TaskList order;
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   new RecursiveTask(2, &order, 1, false));
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   new RecursiveTask(2, &order, 2, false));
-  MessageLoop::current()->PostTask(FROM_HERE, new QuitTask(&order, 3));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&RecursiveFunc, &order, 1, 2, false));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&RecursiveFunc, &order, 2, 2, false));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&QuitFunc, &order, 3));
 
   MessageLoop::current()->Run();
 
   // FIFO order.
-  ASSERT_EQ(14U, order.size());
-  EXPECT_EQ(order[ 0], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[ 1], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[ 2], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[ 3], TaskItem(RECURSIVE, 2, false));
-  EXPECT_EQ(order[ 4], TaskItem(QUITMESSAGELOOP, 3, true));
-  EXPECT_EQ(order[ 5], TaskItem(QUITMESSAGELOOP, 3, false));
-  EXPECT_EQ(order[ 6], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[ 7], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[ 8], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[ 9], TaskItem(RECURSIVE, 2, false));
-  EXPECT_EQ(order[10], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[11], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[12], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[13], TaskItem(RECURSIVE, 2, false));
+  ASSERT_EQ(14U, order.Size());
+  EXPECT_EQ(order.Get(0), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(1), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(2), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(3), TaskItem(RECURSIVE, 2, false));
+  EXPECT_EQ(order.Get(4), TaskItem(QUITMESSAGELOOP, 3, true));
+  EXPECT_EQ(order.Get(5), TaskItem(QUITMESSAGELOOP, 3, false));
+  EXPECT_EQ(order.Get(6), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(7), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(8), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(9), TaskItem(RECURSIVE, 2, false));
+  EXPECT_EQ(order.Get(10), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(11), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(12), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(13), TaskItem(RECURSIVE, 2, false));
 }
 
 void RunTest_RecursiveDenial3(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   EXPECT_TRUE(MessageLoop::current()->NestableTasksAllowed());
   TaskList order;
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   new RecursiveSlowTask(2, &order, 1, false));
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   new RecursiveSlowTask(2, &order, 2, false));
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
-                                          new OrderedTasks(&order, 3), 5);
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
-                                          new QuitTask(&order, 4), 5);
+  MessageLoop::current()->PostClosure(
+      FROM_HERE, base::Bind(&RecursiveSlowFunc, &order, 1, 2, false));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE, base::Bind(&RecursiveSlowFunc, &order, 2, 2, false));
+  MessageLoop::current()->PostDelayedClosure(
+      FROM_HERE, base::Bind(&OrderedFunc, &order, 3), 5);
+  MessageLoop::current()->PostDelayedClosure(
+      FROM_HERE, base::Bind(&QuitFunc, &order, 4), 5);
 
   MessageLoop::current()->Run();
 
   // FIFO order.
-  ASSERT_EQ(16U, order.size());
-  EXPECT_EQ(order[ 0], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[ 1], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[ 2], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[ 3], TaskItem(RECURSIVE, 2, false));
-  EXPECT_EQ(order[ 4], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[ 5], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[ 6], TaskItem(ORDERERD, 3, true));
-  EXPECT_EQ(order[ 7], TaskItem(ORDERERD, 3, false));
-  EXPECT_EQ(order[ 8], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[ 9], TaskItem(RECURSIVE, 2, false));
-  EXPECT_EQ(order[10], TaskItem(QUITMESSAGELOOP, 4, true));
-  EXPECT_EQ(order[11], TaskItem(QUITMESSAGELOOP, 4, false));
-  EXPECT_EQ(order[12], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[13], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[14], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[15], TaskItem(RECURSIVE, 2, false));
+  ASSERT_EQ(16U, order.Size());
+  EXPECT_EQ(order.Get(0), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(1), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(2), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(3), TaskItem(RECURSIVE, 2, false));
+  EXPECT_EQ(order.Get(4), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(5), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(6), TaskItem(ORDERERD, 3, true));
+  EXPECT_EQ(order.Get(7), TaskItem(ORDERERD, 3, false));
+  EXPECT_EQ(order.Get(8), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(9), TaskItem(RECURSIVE, 2, false));
+  EXPECT_EQ(order.Get(10), TaskItem(QUITMESSAGELOOP, 4, true));
+  EXPECT_EQ(order.Get(11), TaskItem(QUITMESSAGELOOP, 4, false));
+  EXPECT_EQ(order.Get(12), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(13), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(14), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(15), TaskItem(RECURSIVE, 2, false));
 }
 
 void RunTest_RecursiveSupport1(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   TaskList order;
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   new RecursiveTask(2, &order, 1, true));
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   new RecursiveTask(2, &order, 2, true));
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   new QuitTask(&order, 3));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&RecursiveFunc, &order, 1, 2, true));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&RecursiveFunc, &order, 2, 2, true));
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&QuitFunc, &order, 3));
 
   MessageLoop::current()->Run();
 
   // FIFO order.
-  ASSERT_EQ(14U, order.size());
-  EXPECT_EQ(order[ 0], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[ 1], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[ 2], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[ 3], TaskItem(RECURSIVE, 2, false));
-  EXPECT_EQ(order[ 4], TaskItem(QUITMESSAGELOOP, 3, true));
-  EXPECT_EQ(order[ 5], TaskItem(QUITMESSAGELOOP, 3, false));
-  EXPECT_EQ(order[ 6], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[ 7], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[ 8], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[ 9], TaskItem(RECURSIVE, 2, false));
-  EXPECT_EQ(order[10], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[11], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[12], TaskItem(RECURSIVE, 2, true));
-  EXPECT_EQ(order[13], TaskItem(RECURSIVE, 2, false));
+  ASSERT_EQ(14U, order.Size());
+  EXPECT_EQ(order.Get(0), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(1), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(2), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(3), TaskItem(RECURSIVE, 2, false));
+  EXPECT_EQ(order.Get(4), TaskItem(QUITMESSAGELOOP, 3, true));
+  EXPECT_EQ(order.Get(5), TaskItem(QUITMESSAGELOOP, 3, false));
+  EXPECT_EQ(order.Get(6), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(7), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(8), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(9), TaskItem(RECURSIVE, 2, false));
+  EXPECT_EQ(order.Get(10), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(11), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(12), TaskItem(RECURSIVE, 2, true));
+  EXPECT_EQ(order.Get(13), TaskItem(RECURSIVE, 2, false));
 }
 
 #if defined(OS_WIN)
 // TODO(darin): These tests need to be ported since they test critical
 // message loop functionality.
 
 // A side effect of this test is the generation a beep. Sorry.
 void RunTest_RecursiveDenial2(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   Thread worker("RecursiveDenial2_worker");
   Thread::Options options;
   options.message_loop_type = message_loop_type;
   ASSERT_EQ(true, worker.StartWithOptions(options));
   TaskList order;
   base::win::ScopedHandle event(CreateEvent(NULL, FALSE, FALSE, NULL));
-  worker.message_loop()->PostTask(FROM_HERE,
-                                  new Recursive2Tasks(MessageLoop::current(),
-                                                      event,
-                                                      true,
-                                                      &order,
-                                                      false));
+  worker.message_loop()->PostClosure(FROM_HERE,
+                                     base::Bind(&RecursiveFuncWin,
+                                                MessageLoop::current(),
+                                                event.Get(),
+                                                true,
+                                                &order,
+                                                false));
   // Let the other thread execute.
   WaitForSingleObject(event, INFINITE);
   MessageLoop::current()->Run();
 
-  ASSERT_EQ(order.size(), 17);
-  EXPECT_EQ(order[ 0], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[ 1], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[ 2], TaskItem(MESSAGEBOX, 2, true));
-  EXPECT_EQ(order[ 3], TaskItem(MESSAGEBOX, 2, false));
-  EXPECT_EQ(order[ 4], TaskItem(RECURSIVE, 3, true));
-  EXPECT_EQ(order[ 5], TaskItem(RECURSIVE, 3, false));
-  // When EndDialogTask is processed, the window is already dismissed, hence no
+  ASSERT_EQ(order.Size(), 17);
+  EXPECT_EQ(order.Get(0), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(1), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(2), TaskItem(MESSAGEBOX, 2, true));
+  EXPECT_EQ(order.Get(3), TaskItem(MESSAGEBOX, 2, false));
+  EXPECT_EQ(order.Get(4), TaskItem(RECURSIVE, 3, true));
+  EXPECT_EQ(order.Get(5), TaskItem(RECURSIVE, 3, false));
+  // When EndDialogFunc is processed, the window is already dismissed, hence no
   // "end" entry.
-  EXPECT_EQ(order[ 6], TaskItem(ENDDIALOG, 4, true));
-  EXPECT_EQ(order[ 7], TaskItem(QUITMESSAGELOOP, 5, true));
-  EXPECT_EQ(order[ 8], TaskItem(QUITMESSAGELOOP, 5, false));
-  EXPECT_EQ(order[ 9], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[10], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[11], TaskItem(RECURSIVE, 3, true));
-  EXPECT_EQ(order[12], TaskItem(RECURSIVE, 3, false));
-  EXPECT_EQ(order[13], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[14], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[15], TaskItem(RECURSIVE, 3, true));
-  EXPECT_EQ(order[16], TaskItem(RECURSIVE, 3, false));
+  EXPECT_EQ(order.Get(6), TaskItem(ENDDIALOG, 4, true));
+  EXPECT_EQ(order.Get(7), TaskItem(QUITMESSAGELOOP, 5, true));
+  EXPECT_EQ(order.Get(8), TaskItem(QUITMESSAGELOOP, 5, false));
+  EXPECT_EQ(order.Get(9), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(10), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(11), TaskItem(RECURSIVE, 3, true));
+  EXPECT_EQ(order.Get(12), TaskItem(RECURSIVE, 3, false));
+  EXPECT_EQ(order.Get(13), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(14), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(15), TaskItem(RECURSIVE, 3, true));
+  EXPECT_EQ(order.Get(16), TaskItem(RECURSIVE, 3, false));
 }
 
 // A side effect of this test is the generation a beep. Sorry.  This test also
 // needs to process windows messages on the current thread.
 void RunTest_RecursiveSupport2(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   Thread worker("RecursiveSupport2_worker");
   Thread::Options options;
   options.message_loop_type = message_loop_type;
   ASSERT_EQ(true, worker.StartWithOptions(options));
   TaskList order;
   base::win::ScopedHandle event(CreateEvent(NULL, FALSE, FALSE, NULL));
-  worker.message_loop()->PostTask(FROM_HERE,
-                                  new Recursive2Tasks(MessageLoop::current(),
-                                                      event,
-                                                      false,
-                                                      &order,
-                                                      true));
+  worker.message_loop()->PostClosure(FROM_HERE,
+                                     base::Bind(&RecursiveFuncWin,
+                                                MessageLoop::current(),
+                                                event.Get(),
+                                                false,
+                                                &order,
+                                                true));
   // Let the other thread execute.
   WaitForSingleObject(event, INFINITE);
   MessageLoop::current()->Run();
 
-  ASSERT_EQ(order.size(), 18);
-  EXPECT_EQ(order[ 0], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[ 1], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[ 2], TaskItem(MESSAGEBOX, 2, true));
+  ASSERT_EQ(order.Size(), 18);
+  EXPECT_EQ(order.Get(0), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(1), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(2), TaskItem(MESSAGEBOX, 2, true));
   // Note that this executes in the MessageBox modal loop.
-  EXPECT_EQ(order[ 3], TaskItem(RECURSIVE, 3, true));
-  EXPECT_EQ(order[ 4], TaskItem(RECURSIVE, 3, false));
-  EXPECT_EQ(order[ 5], TaskItem(ENDDIALOG, 4, true));
-  EXPECT_EQ(order[ 6], TaskItem(ENDDIALOG, 4, false));
-  EXPECT_EQ(order[ 7], TaskItem(MESSAGEBOX, 2, false));
-  /* The order can subtly change here. The reason is that when RecursiveTask(1)
+  EXPECT_EQ(order.Get(3), TaskItem(RECURSIVE, 3, true));
+  EXPECT_EQ(order.Get(4), TaskItem(RECURSIVE, 3, false));
+  EXPECT_EQ(order.Get(5), TaskItem(ENDDIALOG, 4, true));
+  EXPECT_EQ(order.Get(6), TaskItem(ENDDIALOG, 4, false));
+  EXPECT_EQ(order.Get(7), TaskItem(MESSAGEBOX, 2, false));
+  /* The order can subtly change here. The reason is that when RecursiveFunc(1)
      is called in the main thread, if it is faster than getting to the
-     PostTask(FROM_HERE, QuitTask) execution, the order of task execution can
-     change. We don't care anyway that the order isn't correct.
-  EXPECT_EQ(order[ 8], TaskItem(QUITMESSAGELOOP, 5, true));
-  EXPECT_EQ(order[ 9], TaskItem(QUITMESSAGELOOP, 5, false));
-  EXPECT_EQ(order[10], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[11], TaskItem(RECURSIVE, 1, false));
+     PostClosure(FROM_HERE, base::Bind(&QuitFunc) execution, the order of task
+     execution can change. We don't care anyway that the order isn't correct.
+  EXPECT_EQ(order.Get(8), TaskItem(QUITMESSAGELOOP, 5, true));
+  EXPECT_EQ(order.Get(9), TaskItem(QUITMESSAGELOOP, 5, false));
+  EXPECT_EQ(order.Get(10), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(11), TaskItem(RECURSIVE, 1, false));
   */
-  EXPECT_EQ(order[12], TaskItem(RECURSIVE, 3, true));
-  EXPECT_EQ(order[13], TaskItem(RECURSIVE, 3, false));
-  EXPECT_EQ(order[14], TaskItem(RECURSIVE, 1, true));
-  EXPECT_EQ(order[15], TaskItem(RECURSIVE, 1, false));
-  EXPECT_EQ(order[16], TaskItem(RECURSIVE, 3, true));
-  EXPECT_EQ(order[17], TaskItem(RECURSIVE, 3, false));
+  EXPECT_EQ(order.Get(12), TaskItem(RECURSIVE, 3, true));
+  EXPECT_EQ(order.Get(13), TaskItem(RECURSIVE, 3, false));
+  EXPECT_EQ(order.Get(14), TaskItem(RECURSIVE, 1, true));
+  EXPECT_EQ(order.Get(15), TaskItem(RECURSIVE, 1, false));
+  EXPECT_EQ(order.Get(16), TaskItem(RECURSIVE, 3, true));
+  EXPECT_EQ(order.Get(17), TaskItem(RECURSIVE, 3, false));
 }
 
 #endif  // defined(OS_WIN)
 
-class TaskThatPumps : public OrderedTasks {
- public:
-  TaskThatPumps(TaskList* order, int cookie)
-      : OrderedTasks(order, PUMPS, cookie) {
-  }
-
-  virtual void Run() {
-    RunStart();
-    bool old_state = MessageLoop::current()->NestableTasksAllowed();
-    MessageLoop::current()->SetNestableTasksAllowed(true);
-    MessageLoop::current()->RunAllPending();
-    MessageLoop::current()->SetNestableTasksAllowed(old_state);
-    RunEnd();
-  }
-};
+void FuncThatPumps(TaskList* order, int cookie) {
+  order->RecordStart(PUMPS, cookie);
+  bool old_state = MessageLoop::current()->NestableTasksAllowed();
+  MessageLoop::current()->SetNestableTasksAllowed(true);
+  MessageLoop::current()->RunAllPending();
+  MessageLoop::current()->SetNestableTasksAllowed(old_state);
+  order->RecordEnd(PUMPS, cookie);
+}
 
 // Tests that non nestable tasks run in FIFO if there are no nested loops.
-void RunTest_NonNestableWithNoNesting(MessageLoop::Type message_loop_type) {
+void RunTest_NonNestableWithNoNesting(
+    MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   TaskList order;
 
-  Task* task = new OrderedTasks(&order, 1);
-  MessageLoop::current()->PostNonNestableTask(FROM_HERE, task);
-  MessageLoop::current()->PostTask(FROM_HERE, new OrderedTasks(&order, 2));
-  MessageLoop::current()->PostTask(FROM_HERE, new QuitTask(&order, 3));
+  MessageLoop::current()->PostNonNestableClosure(
+      FROM_HERE,
+      base::Bind(&OrderedFunc, &order, 1));
+  MessageLoop::current()->PostClosure(FROM_HERE,
+                                      base::Bind(&OrderedFunc, &order, 2));
+  MessageLoop::current()->PostClosure(FROM_HERE,
+                                      base::Bind(&QuitFunc, &order, 3));
   MessageLoop::current()->Run();
 
   // FIFO order.
-  ASSERT_EQ(6U, order.size());
-  EXPECT_EQ(order[ 0], TaskItem(ORDERERD, 1, true));
-  EXPECT_EQ(order[ 1], TaskItem(ORDERERD, 1, false));
-  EXPECT_EQ(order[ 2], TaskItem(ORDERERD, 2, true));
-  EXPECT_EQ(order[ 3], TaskItem(ORDERERD, 2, false));
-  EXPECT_EQ(order[ 4], TaskItem(QUITMESSAGELOOP, 3, true));
-  EXPECT_EQ(order[ 5], TaskItem(QUITMESSAGELOOP, 3, false));
+  ASSERT_EQ(6U, order.Size());
+  EXPECT_EQ(order.Get(0), TaskItem(ORDERERD, 1, true));
+  EXPECT_EQ(order.Get(1), TaskItem(ORDERERD, 1, false));
+  EXPECT_EQ(order.Get(2), TaskItem(ORDERERD, 2, true));
+  EXPECT_EQ(order.Get(3), TaskItem(ORDERERD, 2, false));
+  EXPECT_EQ(order.Get(4), TaskItem(QUITMESSAGELOOP, 3, true));
+  EXPECT_EQ(order.Get(5), TaskItem(QUITMESSAGELOOP, 3, false));
 }
 
 // Tests that non nestable tasks don't run when there's code in the call stack.
 void RunTest_NonNestableInNestedLoop(MessageLoop::Type message_loop_type,
                                      bool use_delayed) {
   MessageLoop loop(message_loop_type);
 
   TaskList order;
 
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   new TaskThatPumps(&order, 1));
-  Task* task = new OrderedTasks(&order, 2);
+  MessageLoop::current()->PostClosure(
+      FROM_HERE,
+      base::Bind(&FuncThatPumps, &order, 1));
   if (use_delayed) {
-    MessageLoop::current()->PostNonNestableDelayedTask(FROM_HERE, task, 1);
+    MessageLoop::current()->PostNonNestableDelayedClosure(
+        FROM_HERE,
+        base::Bind(&OrderedFunc, &order, 2),
+        1);
   } else {
-    MessageLoop::current()->PostNonNestableTask(FROM_HERE, task);
+    MessageLoop::current()->PostNonNestableClosure(
+        FROM_HERE,
+        base::Bind(&OrderedFunc, &order, 2));
   }
-  MessageLoop::current()->PostTask(FROM_HERE, new OrderedTasks(&order, 3));
-  MessageLoop::current()->PostTask(FROM_HERE, new SleepTask(&order, 4, 50));
-  MessageLoop::current()->PostTask(FROM_HERE, new OrderedTasks(&order, 5));
-  Task* non_nestable_quit = new QuitTask(&order, 6);
+  MessageLoop::current()->PostClosure(FROM_HERE,
+                                      base::Bind(&OrderedFunc, &order, 3));
+  MessageLoop::current()->PostClosure(FROM_HERE,
+                                      base::Bind(&SleepFunc, &order, 4, 50));
+  MessageLoop::current()->PostClosure(FROM_HERE,
+                                      base::Bind(&OrderedFunc, &order, 5));
   if (use_delayed) {
-    MessageLoop::current()->PostNonNestableDelayedTask(FROM_HERE,
-                                                       non_nestable_quit,
-                                                       2);
+    MessageLoop::current()->PostNonNestableDelayedClosure(
+        FROM_HERE,
+        base::Bind(&QuitFunc, &order, 6),
+        2);
   } else {
-    MessageLoop::current()->PostNonNestableTask(FROM_HERE, non_nestable_quit);
+    MessageLoop::current()->PostNonNestableClosure(
+        FROM_HERE,
+        base::Bind(&QuitFunc, &order, 6));
   }
 
   MessageLoop::current()->Run();
 
   // FIFO order.
-  ASSERT_EQ(12U, order.size());
-  EXPECT_EQ(order[ 0], TaskItem(PUMPS, 1, true));
-  EXPECT_EQ(order[ 1], TaskItem(ORDERERD, 3, true));
-  EXPECT_EQ(order[ 2], TaskItem(ORDERERD, 3, false));
-  EXPECT_EQ(order[ 3], TaskItem(SLEEP, 4, true));
-  EXPECT_EQ(order[ 4], TaskItem(SLEEP, 4, false));
-  EXPECT_EQ(order[ 5], TaskItem(ORDERERD, 5, true));
-  EXPECT_EQ(order[ 6], TaskItem(ORDERERD, 5, false));
-  EXPECT_EQ(order[ 7], TaskItem(PUMPS, 1, false));
-  EXPECT_EQ(order[ 8], TaskItem(ORDERERD, 2, true));
-  EXPECT_EQ(order[ 9], TaskItem(ORDERERD, 2, false));
-  EXPECT_EQ(order[10], TaskItem(QUITMESSAGELOOP, 6, true));
-  EXPECT_EQ(order[11], TaskItem(QUITMESSAGELOOP, 6, false));
+  ASSERT_EQ(12U, order.Size());
+  EXPECT_EQ(order.Get(0), TaskItem(PUMPS, 1, true));
+  EXPECT_EQ(order.Get(1), TaskItem(ORDERERD, 3, true));
+  EXPECT_EQ(order.Get(2), TaskItem(ORDERERD, 3, false));
+  EXPECT_EQ(order.Get(3), TaskItem(SLEEP, 4, true));
+  EXPECT_EQ(order.Get(4), TaskItem(SLEEP, 4, false));
+  EXPECT_EQ(order.Get(5), TaskItem(ORDERERD, 5, true));
+  EXPECT_EQ(order.Get(6), TaskItem(ORDERERD, 5, false));
+  EXPECT_EQ(order.Get(7), TaskItem(PUMPS, 1, false));
+  EXPECT_EQ(order.Get(8), TaskItem(ORDERERD, 2, true));
+  EXPECT_EQ(order.Get(9), TaskItem(ORDERERD, 2, false));
+  EXPECT_EQ(order.Get(10), TaskItem(QUITMESSAGELOOP, 6, true));
+  EXPECT_EQ(order.Get(11), TaskItem(QUITMESSAGELOOP, 6, false));
 }
 
 #if defined(OS_WIN)
 
 class DispatcherImpl : public MessageLoopForUI::Dispatcher {
  public:
   DispatcherImpl() : dispatch_count_(0) {}
 
   virtual bool Dispatch(const MSG& msg) {
     ::TranslateMessage(&msg);
     ::DispatchMessage(&msg);
     // Do not count WM_TIMER since it is not what we post and it will cause
     // flakiness.
     if (msg.message != WM_TIMER)
       ++dispatch_count_;
     // We treat WM_LBUTTONUP as the last message.
     return msg.message != WM_LBUTTONUP;
   }
 
   int dispatch_count_;
 };
 
+void MouseDownUp() {
+  PostMessage(NULL, WM_LBUTTONDOWN, 0, 0);
+  PostMessage(NULL, WM_LBUTTONUP, 'A', 0);
+}
+
 void RunTest_Dispatcher(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
-  class MyTask : public Task {
-  public:
-    virtual void Run() {
-      PostMessage(NULL, WM_LBUTTONDOWN, 0, 0);
-      PostMessage(NULL, WM_LBUTTONUP, 'A', 0);
-    }
-  };
-  Task* task = new MyTask();
-  MessageLoop::current()->PostDelayedTask(FROM_HERE, task, 100);
+  MessageLoop::current()->PostDelayedClosure(FROM_HERE,
+                                             base::Bind(&MouseDownUp), 100);
   DispatcherImpl dispatcher;
   MessageLoopForUI::current()->Run(&dispatcher);
   ASSERT_EQ(2, dispatcher.dispatch_count_);
 }
 
 LRESULT CALLBACK MsgFilterProc(int code, WPARAM wparam, LPARAM lparam) {
   if (code == base::MessagePumpForUI::kMessageFilterCode) {
     MSG* msg = reinterpret_cast<MSG*>(lparam);
     if (msg->message == WM_LBUTTONDOWN)
       return TRUE;
   }
   return FALSE;
 }
 
 void RunTest_DispatcherWithMessageHook(MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
-  class MyTask : public Task {
-  public:
-    virtual void Run() {
-      PostMessage(NULL, WM_LBUTTONDOWN, 0, 0);
-      PostMessage(NULL, WM_LBUTTONUP, 'A', 0);
-    }
-  };
-  Task* task = new MyTask();
-  MessageLoop::current()->PostDelayedTask(FROM_HERE, task, 100);
+  MessageLoop::current()->PostDelayedClosure(FROM_HERE,
+                                             base::Bind(&MouseDownUp), 100);
   HHOOK msg_hook = SetWindowsHookEx(WH_MSGFILTER,
                                     MsgFilterProc,
                                     NULL,
                                     GetCurrentThreadId());
   DispatcherImpl dispatcher;
   MessageLoopForUI::current()->Run(&dispatcher);
   ASSERT_EQ(1, dispatcher.dispatch_count_);
   UnhookWindowsHookEx(msg_hook);
 }
 
@@ skipping 42 matching lines @@
                                   DWORD bytes_transfered, DWORD error) {
   ASSERT_TRUE(context == &context_);
   ASSERT_TRUE(SetEvent(signal_));
 }
 
 void TestIOHandler::WaitForIO() {
   EXPECT_TRUE(MessageLoopForIO::current()->WaitForIOCompletion(300, this));
   EXPECT_TRUE(MessageLoopForIO::current()->WaitForIOCompletion(400, this));
 }
 
-class IOHandlerTask : public Task {
- public:
-  explicit IOHandlerTask(TestIOHandler* handler) : handler_(handler) {}
-  virtual void Run() {
-    handler_->Init();
-  }
-
- private:
-  TestIOHandler* handler_;
-};
-
 void RunTest_IOHandler() {
   base::win::ScopedHandle callback_called(CreateEvent(NULL, TRUE, FALSE, NULL));
   ASSERT_TRUE(callback_called.IsValid());
 
   const wchar_t* kPipeName = L"\\\\.\\pipe\\iohandler_pipe";
   base::win::ScopedHandle server(
       CreateNamedPipe(kPipeName, PIPE_ACCESS_OUTBOUND, 0, 1, 0, 0, 0, NULL));
   ASSERT_TRUE(server.IsValid());
 
   Thread thread("IOHandler test");
   Thread::Options options;
   options.message_loop_type = MessageLoop::TYPE_IO;
   ASSERT_TRUE(thread.StartWithOptions(options));
 
   MessageLoop* thread_loop = thread.message_loop();
   ASSERT_TRUE(NULL != thread_loop);
 
   TestIOHandler handler(kPipeName, callback_called, false);
-  IOHandlerTask* task = new IOHandlerTask(&handler);
-  thread_loop->PostTask(FROM_HERE, task);
+  thread_loop->PostClosure(FROM_HERE, base::Bind(&TestIOHandler::Init,
+                                                 base::Unretained(&handler)));
   Sleep(100);  // Make sure the thread runs and sleeps for lack of work.
 
   const char buffer[] = "Hello there!";
   DWORD written;
   EXPECT_TRUE(WriteFile(server, buffer, sizeof(buffer), &written, NULL));
 
   DWORD result = WaitForSingleObject(callback_called, 1000);
   EXPECT_EQ(WAIT_OBJECT_0, result);
 
   thread.Stop();
@@ skipping 19 matching lines @@
   Thread thread("IOHandler test");
   Thread::Options options;
   options.message_loop_type = MessageLoop::TYPE_IO;
   ASSERT_TRUE(thread.StartWithOptions(options));
 
   MessageLoop* thread_loop = thread.message_loop();
   ASSERT_TRUE(NULL != thread_loop);
 
   TestIOHandler handler1(kPipeName1, callback1_called, false);
   TestIOHandler handler2(kPipeName2, callback2_called, true);
-  IOHandlerTask* task1 = new IOHandlerTask(&handler1);
-  IOHandlerTask* task2 = new IOHandlerTask(&handler2);
-  thread_loop->PostTask(FROM_HERE, task1);
+  thread_loop->PostClosure(FROM_HERE, base::Bind(&TestIOHandler::Init,
+                                                 base::Unretained(&handler1)));
+  // TODO(ajwong): Do we really need such long Sleeps in ths function?
   Sleep(100);  // Make sure the thread runs and sleeps for lack of work.
-  thread_loop->PostTask(FROM_HERE, task2);
+  thread_loop->PostClosure(FROM_HERE, base::Bind(&TestIOHandler::Init,
+                                                 base::Unretained(&handler2)));
   Sleep(100);
 
   // At this time handler1 is waiting to be called, and the thread is waiting
   // on the Init method of handler2, filtering only handler2 callbacks.
 
   const char buffer[] = "Hello there!";
   DWORD written;
   EXPECT_TRUE(WriteFile(server1, buffer, sizeof(buffer), &written, NULL));
   Sleep(200);
   EXPECT_EQ(WAIT_TIMEOUT, WaitForSingleObject(callback1_called, 0)) <<
@@ skipping 16 matching lines @@
 // Each test is run against each type of MessageLoop.  That way we are sure
 // that message loops work properly in all configurations.  Of course, in some
 // cases, a unit test may only be for a particular type of loop.
 
 TEST(MessageLoopTest, PostTask) {
   RunTest_PostTask(MessageLoop::TYPE_DEFAULT);
   RunTest_PostTask(MessageLoop::TYPE_UI);
   RunTest_PostTask(MessageLoop::TYPE_IO);
 }
 
-TEST(MessageLoopTest, PostTask_SEH) {
-  RunTest_PostTask_SEH(MessageLoop::TYPE_DEFAULT);
-  RunTest_PostTask_SEH(MessageLoop::TYPE_UI);
-  RunTest_PostTask_SEH(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, PostClosure) {
+  RunTest_PostClosure(MessageLoop::TYPE_DEFAULT);
+  RunTest_PostClosure(MessageLoop::TYPE_UI);
+  RunTest_PostClosure(MessageLoop::TYPE_IO);
 }
 
-TEST(MessageLoopTest, PostDelayedTask_Basic) {
-  RunTest_PostDelayedTask_Basic(MessageLoop::TYPE_DEFAULT);
-  RunTest_PostDelayedTask_Basic(MessageLoop::TYPE_UI);
-  RunTest_PostDelayedTask_Basic(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, PostClosure_SEH) {
+  RunTest_PostClosure_SEH(MessageLoop::TYPE_DEFAULT);
+  RunTest_PostClosure_SEH(MessageLoop::TYPE_UI);
+  RunTest_PostClosure_SEH(MessageLoop::TYPE_IO);
 }
 
-TEST(MessageLoopTest, PostDelayedTask_InDelayOrder) {
-  RunTest_PostDelayedTask_InDelayOrder(MessageLoop::TYPE_DEFAULT);
-  RunTest_PostDelayedTask_InDelayOrder(MessageLoop::TYPE_UI);
-  RunTest_PostDelayedTask_InDelayOrder(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, PostDelayedClosure_Basic) {
+  RunTest_PostDelayedClosure_Basic(MessageLoop::TYPE_DEFAULT);
+  RunTest_PostDelayedClosure_Basic(MessageLoop::TYPE_UI);
+  RunTest_PostDelayedClosure_Basic(MessageLoop::TYPE_IO);
 }
 
-TEST(MessageLoopTest, PostDelayedTask_InPostOrder) {
-  RunTest_PostDelayedTask_InPostOrder(MessageLoop::TYPE_DEFAULT);
-  RunTest_PostDelayedTask_InPostOrder(MessageLoop::TYPE_UI);
-  RunTest_PostDelayedTask_InPostOrder(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, PostDelayedClosure_InDelayOrder) {
+  RunTest_PostDelayedClosure_InDelayOrder(MessageLoop::TYPE_DEFAULT);
+  RunTest_PostDelayedClosure_InDelayOrder(MessageLoop::TYPE_UI);
+  RunTest_PostDelayedClosure_InDelayOrder(MessageLoop::TYPE_IO);
 }
 
-TEST(MessageLoopTest, PostDelayedTask_InPostOrder_2) {
-  RunTest_PostDelayedTask_InPostOrder_2(MessageLoop::TYPE_DEFAULT);
-  RunTest_PostDelayedTask_InPostOrder_2(MessageLoop::TYPE_UI);
-  RunTest_PostDelayedTask_InPostOrder_2(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, PostDelayedClosure_InPostOrder) {
+  RunTest_PostDelayedClosure_InPostOrder(MessageLoop::TYPE_DEFAULT);
+  RunTest_PostDelayedClosure_InPostOrder(MessageLoop::TYPE_UI);
+  RunTest_PostDelayedClosure_InPostOrder(MessageLoop::TYPE_IO);
 }
 
-TEST(MessageLoopTest, PostDelayedTask_InPostOrder_3) {
-  RunTest_PostDelayedTask_InPostOrder_3(MessageLoop::TYPE_DEFAULT);
-  RunTest_PostDelayedTask_InPostOrder_3(MessageLoop::TYPE_UI);
-  RunTest_PostDelayedTask_InPostOrder_3(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, PostDelayedClosure_InPostOrder_2) {
+  RunTest_PostDelayedClosure_InPostOrder_2(MessageLoop::TYPE_DEFAULT);
+  RunTest_PostDelayedClosure_InPostOrder_2(MessageLoop::TYPE_UI);
+  RunTest_PostDelayedClosure_InPostOrder_2(MessageLoop::TYPE_IO);
 }
 
-TEST(MessageLoopTest, PostDelayedTask_SharedTimer) {
-  RunTest_PostDelayedTask_SharedTimer(MessageLoop::TYPE_DEFAULT);
-  RunTest_PostDelayedTask_SharedTimer(MessageLoop::TYPE_UI);
-  RunTest_PostDelayedTask_SharedTimer(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, PostDelayedClosure_InPostOrder_3) {
+  RunTest_PostDelayedClosure_InPostOrder_3(MessageLoop::TYPE_DEFAULT);
+  RunTest_PostDelayedClosure_InPostOrder_3(MessageLoop::TYPE_UI);
+  RunTest_PostDelayedClosure_InPostOrder_3(MessageLoop::TYPE_IO);
+}
+
+TEST(MessageLoopTest, PostDelayedClosure_SharedTimer) {
+  RunTest_PostDelayedClosure_SharedTimer(MessageLoop::TYPE_DEFAULT);
+  RunTest_PostDelayedClosure_SharedTimer(MessageLoop::TYPE_UI);
+  RunTest_PostDelayedClosure_SharedTimer(MessageLoop::TYPE_IO);
 }
 
 #if defined(OS_WIN)
-TEST(MessageLoopTest, PostDelayedTask_SharedTimer_SubPump) {
-  RunTest_PostDelayedTask_SharedTimer_SubPump();
+TEST(MessageLoopTest, PostDelayedClosure_SharedTimer_SubPump) {
+  RunTest_PostDelayedClosure_SharedTimer_SubPump();
 }
 #endif
 
 // TODO(darin): MessageLoop does not support deleting all tasks in the
 // destructor.
 // Fails, http://crbug.com/50272.
-TEST(MessageLoopTest, FAILS_EnsureTaskDeletion) {
-  RunTest_EnsureTaskDeletion(MessageLoop::TYPE_DEFAULT);
-  RunTest_EnsureTaskDeletion(MessageLoop::TYPE_UI);
-  RunTest_EnsureTaskDeletion(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, FAILS_EnsureDeletion) {
+  RunTest_EnsureDeletion(MessageLoop::TYPE_DEFAULT);
+  RunTest_EnsureDeletion(MessageLoop::TYPE_UI);
+  RunTest_EnsureDeletion(MessageLoop::TYPE_IO);
 }
 
 // TODO(darin): MessageLoop does not support deleting all tasks in the
 // destructor.
 // Fails, http://crbug.com/50272.
-TEST(MessageLoopTest, FAILS_EnsureTaskDeletion_Chain) {
-  RunTest_EnsureTaskDeletion_Chain(MessageLoop::TYPE_DEFAULT);
-  RunTest_EnsureTaskDeletion_Chain(MessageLoop::TYPE_UI);
-  RunTest_EnsureTaskDeletion_Chain(MessageLoop::TYPE_IO);
+TEST(MessageLoopTest, FAILS_EnsureDeletion_Chain) {
+  RunTest_EnsureDeletion_Chain(MessageLoop::TYPE_DEFAULT);
+  RunTest_EnsureDeletion_Chain(MessageLoop::TYPE_UI);
+  RunTest_EnsureDeletion_Chain(MessageLoop::TYPE_IO);
 }
 
 #if defined(OS_WIN)
 TEST(MessageLoopTest, Crasher) {
   RunTest_Crasher(MessageLoop::TYPE_DEFAULT);
   RunTest_Crasher(MessageLoop::TYPE_UI);
   RunTest_Crasher(MessageLoop::TYPE_IO);
 }
 
 TEST(MessageLoopTest, CrasherNasty) {
@@ skipping 52 matching lines @@
   RunTest_NonNestableInNestedLoop(MessageLoop::TYPE_UI, false);
   RunTest_NonNestableInNestedLoop(MessageLoop::TYPE_IO, false);
 }
 
 TEST(MessageLoopTest, NonNestableDelayedInNestedLoop) {
   RunTest_NonNestableInNestedLoop(MessageLoop::TYPE_DEFAULT, true);
   RunTest_NonNestableInNestedLoop(MessageLoop::TYPE_UI, true);
   RunTest_NonNestableInNestedLoop(MessageLoop::TYPE_IO, true);
 }
 
-class DummyTask : public Task {
+void PostNClosuresThenQuit(int posts_remaining) {
+  if (posts_remaining > 1) {
+    MessageLoop::current()->PostClosure(
+        FROM_HERE,
+        base::Bind(&PostNClosuresThenQuit, posts_remaining - 1));
+  } else {
+    MessageLoop::current()->Quit();
+  }
+}
+
+class DummyClosureObserver : public MessageLoop::ClosureObserver {
  public:
-  explicit DummyTask(int num_tasks) : num_tasks_(num_tasks) {}
+  explicit DummyClosureObserver(int num_closures)
+      : num_closures_started_(0),
+        num_closures_processed_(0),
+        num_closures_(num_closures) {}
 
-  virtual void Run() {
-    if (num_tasks_ > 1) {
-      MessageLoop::current()->PostTask(
-          FROM_HERE,
-          new DummyTask(num_tasks_ - 1));
-    } else {
-      MessageLoop::current()->Quit();
-    }
+  virtual ~DummyClosureObserver() {}
+
+  virtual void WillProcessClosure(TimeTicks time_posted) OVERRIDE {
+    num_closures_started_++;
+    EXPECT_TRUE(time_posted != TimeTicks());
+    EXPECT_LE(num_closures_started_, num_closures_);
+    EXPECT_EQ(num_closures_started_, num_closures_processed_ + 1);
   }
 
+  virtual void DidProcessClosure(TimeTicks time_posted) OVERRIDE {
+    num_closures_processed_++;
+    EXPECT_TRUE(time_posted != TimeTicks());
+    EXPECT_LE(num_closures_started_, num_closures_);
+    EXPECT_EQ(num_closures_started_, num_closures_processed_);
+  }
+
+  int num_closures_started() const { return num_closures_started_; }
+  int num_closures_processed() const { return num_closures_processed_; }
+
  private:
-  const int num_tasks_;
+  int num_closures_started_;
+  int num_closures_processed_;
+  const int num_closures_;
+
+  DISALLOW_COPY_AND_ASSIGN(DummyClosureObserver);
 };
 
-class DummyTaskObserver : public MessageLoop::TaskObserver {
- public:
-  explicit DummyTaskObserver(int num_tasks)
-      : num_tasks_started_(0),
-        num_tasks_processed_(0),
-        num_tasks_(num_tasks) {}
-
-  virtual ~DummyTaskObserver() {}
-
-  virtual void WillProcessTask(const Task* task) {
-    num_tasks_started_++;
-    EXPECT_TRUE(task != NULL);
-    EXPECT_LE(num_tasks_started_, num_tasks_);
-    EXPECT_EQ(num_tasks_started_, num_tasks_processed_ + 1);
-  }
-
-  virtual void DidProcessTask(const Task* task) {
-    num_tasks_processed_++;
-    EXPECT_TRUE(task != NULL);
-    EXPECT_LE(num_tasks_started_, num_tasks_);
-    EXPECT_EQ(num_tasks_started_, num_tasks_processed_);
-  }
-
-  int num_tasks_started() const { return num_tasks_started_; }
-  int num_tasks_processed() const { return num_tasks_processed_; }
-
- private:
-  int num_tasks_started_;
-  int num_tasks_processed_;
-  const int num_tasks_;
-
-  DISALLOW_COPY_AND_ASSIGN(DummyTaskObserver);
-};
-
-TEST(MessageLoopTest, TaskObserver) {
-  const int kNumTasks = 6;
-  DummyTaskObserver observer(kNumTasks);
+TEST(MessageLoopTest, ClosureObserver) {
+  const int kNumPosts = 6;
+  DummyClosureObserver observer(kNumPosts);
 
   MessageLoop loop;
-  loop.AddTaskObserver(&observer);
-  loop.PostTask(FROM_HERE, new DummyTask(kNumTasks));
+  loop.AddClosureObserver(&observer);
+  loop.PostClosure(FROM_HERE, base::Bind(&PostNClosuresThenQuit, kNumPosts));
   loop.Run();
-  loop.RemoveTaskObserver(&observer);
+  loop.RemoveClosureObserver(&observer);
 
-  EXPECT_EQ(kNumTasks, observer.num_tasks_started());
-  EXPECT_EQ(kNumTasks, observer.num_tasks_processed());
+  EXPECT_EQ(kNumPosts, observer.num_closures_started());
+  EXPECT_EQ(kNumPosts, observer.num_closures_processed());
 }
 
 #if defined(OS_WIN)
 TEST(MessageLoopTest, Dispatcher) {
   // This test requires a UI loop
   RunTest_Dispatcher(MessageLoop::TYPE_UI);
 }
 
 TEST(MessageLoopTest, DispatcherWithMessageHook) {
   // This test requires a UI loop
@@ skipping 10 matching lines @@
 
 TEST(MessageLoopTest, HighResolutionTimer) {
   MessageLoop loop;
 
   const int kFastTimerMs = 5;
   const int kSlowTimerMs = 100;
 
   EXPECT_FALSE(loop.high_resolution_timers_enabled());
 
   // Post a fast task to enable the high resolution timers.
-  loop.PostDelayedTask(FROM_HERE, new DummyTask(1), kFastTimerMs);
+  loop.PostDelayedClosure(FROM_HERE, base::Bind(&PostNClosuresThenQuit, 1),
+                          kFastTimerMs);
   loop.Run();
   EXPECT_TRUE(loop.high_resolution_timers_enabled());
 
   // Post a slow task and verify high resolution timers
   // are still enabled.
-  loop.PostDelayedTask(FROM_HERE, new DummyTask(1), kSlowTimerMs);
+  loop.PostDelayedClosure(FROM_HERE, base::Bind(&PostNClosuresThenQuit, 1),
+                          kSlowTimerMs);
   loop.Run();
   EXPECT_TRUE(loop.high_resolution_timers_enabled());
 
   // Wait for a while so that high-resolution mode elapses.
   Sleep(MessageLoop::kHighResolutionTimerModeLeaseTimeMs);
 
   // Post a slow task to disable the high resolution timers.
-  loop.PostDelayedTask(FROM_HERE, new DummyTask(1), kSlowTimerMs);
+  loop.PostDelayedClosure(FROM_HERE, base::Bind(&PostNClosuresThenQuit, 1),
+                          kSlowTimerMs);
   loop.Run();
   EXPECT_FALSE(loop.high_resolution_timers_enabled());
 }
 
 #endif  // defined(OS_WIN)
 
 #if defined(OS_POSIX) && !defined(OS_NACL)
 
 namespace {
 
@@ skipping 59 matching lines @@
     PLOG(ERROR) << "close";
   if (HANDLE_EINTR(close(pipefds[1])) < 0)
     PLOG(ERROR) << "close";
 }
 
 }  // namespace
 
 #endif  // defined(OS_POSIX) && !defined(OS_NACL)
 
 namespace {
-class RunAtDestructionTask : public Task {
+class DestructionObserverProbe :
+  public base::RefCounted<DestructionObserverProbe> {
  public:
-  RunAtDestructionTask(bool* task_destroyed, bool* destruction_observer_called)
+  DestructionObserverProbe(bool* task_destroyed,
+                           bool* destruction_observer_called)
       : task_destroyed_(task_destroyed),
         destruction_observer_called_(destruction_observer_called) {
   }
-  ~RunAtDestructionTask() {
+  virtual ~DestructionObserverProbe() {
     EXPECT_FALSE(*destruction_observer_called_);
     *task_destroyed_ = true;
   }
   virtual void Run() {
     // This task should never run.
     ADD_FAILURE();
   }
  private:
   bool* task_destroyed_;
   bool* destruction_observer_called_;
@@ skipping 25 matching lines @@
   // Verify that the destruction observer gets called at the very end (after
   // all the pending tasks have been destroyed).
   MessageLoop* loop = new MessageLoop;
   const int kDelayMS = 100;
 
   bool task_destroyed = false;
   bool destruction_observer_called = false;
 
   MLDestructionObserver observer(&task_destroyed, &destruction_observer_called);
   loop->AddDestructionObserver(&observer);
-  loop->PostDelayedTask(
+  loop->PostDelayedClosure(
       FROM_HERE,
-      new RunAtDestructionTask(&task_destroyed, &destruction_observer_called),
+      base::Bind(&DestructionObserverProbe::Run,
+                 new DestructionObserverProbe(&task_destroyed,
+                                              &destruction_observer_called)),
       kDelayMS);
   delete loop;
   EXPECT_TRUE(observer.task_destroyed_before_message_loop());
   // The task should have been destroyed when we deleted the loop.
   EXPECT_TRUE(task_destroyed);
   EXPECT_TRUE(destruction_observer_called);
 }