Revert 211956 "base: Change WeakPtr to use SequenceChecker inste..."

As well as revert 212725 "base: Make SequenceChecker death tests multi-threads work correctly." 

See http://crbug.com/261448 

> base: Change WeakPtr to use SequenceChecker instead of ThreadChecker. 
> 
> This will enable WeakPtr to be used in SequencedWorkerPool, et al. with a sequence token. 
> 
> This is a continuation of issue: https://chromiumcodereview.appspot.com/18231002/ 
> 
> The original issue got messed up by a rietveld bug, so refer there for history and comments. 
> 
> BUG=165590
> 
> Review URL: https://chromiumcodereview.appspot.com/18501008 

TBR=tommycli@chromium.org

Review URL: https://chromiumcodereview.appspot.com/19695005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@212780 0039d316-1c4b-4281-b951-d872f2087c98

13 files changed, 296 insertions, 384 deletions

diff --git a/base/base.gyp b/base/base.gyp
index 972ff3c..56a036a 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -570,6 +570,7 @@
         'scoped_observer.h',
         'security_unittest.cc',
         'sequence_checker_unittest.cc',
+        'sequence_checker_impl_unittest.cc',
         'sha1_unittest.cc',
         'stl_util_unittest.cc',
         'strings/nullable_string16_unittest.cc',
diff --git a/base/memory/weak_ptr.cc b/base/memory/weak_ptr.cc
index d9ce86a..a22f61a 100644
--- a/base/memory/weak_ptr.cc
+++ b/base/memory/weak_ptr.cc
@@ -10,21 +10,21 @@ namespace internal {
 WeakReference::Flag::Flag() : is_valid_(true) {
   // Flags only become bound when checked for validity, or invalidated,
   // so that we can check that later validity/invalidation operations on
-  // the same Flag take place on the same sequenced thread.
-  sequence_checker_.DetachFromSequence();
+  // the same Flag take place on the same thread.
+  thread_checker_.DetachFromThread();
 }
 
 void WeakReference::Flag::Invalidate() {
   // The flag being invalidated with a single ref implies that there are no
   // weak pointers in existence. Allow deletion on other thread in this case.
-  DCHECK(sequence_checker_.CalledOnValidSequencedThread() || HasOneRef())
-      << "WeakPtrs must be invalidated on the same sequenced thread.";
+  DCHECK(thread_checker_.CalledOnValidThread() || HasOneRef())
+      << "WeakPtrs must be checked and invalidated on the same thread.";
   is_valid_ = false;
 }
 
 bool WeakReference::Flag::IsValid() const {
-  DCHECK(sequence_checker_.CalledOnValidSequencedThread())
-      << "WeakPtrs must be checked on the same sequenced thread.";
+  DCHECK(thread_checker_.CalledOnValidThread())
+      << "WeakPtrs must be checked and invalidated on the same thread.";
   return is_valid_;
 }
 
diff --git a/base/memory/weak_ptr.h b/base/memory/weak_ptr.h
index b4120a1..621c0fa 100644
--- a/base/memory/weak_ptr.h
+++ b/base/memory/weak_ptr.h
@@ -67,8 +67,8 @@
 #include "base/base_export.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
-#include "base/sequence_checker.h"
 #include "base/template_util.h"
+#include "base/threading/thread_checker.h"
 
 namespace base {
 
@@ -91,14 +91,14 @@ class BASE_EXPORT WeakReference {
     bool IsValid() const;
 
     // Remove this when crbug.com/234964 is addressed.
-    void DetachFromThreadHack() { sequence_checker_.DetachFromSequence(); }
+    void DetachFromThreadHack() { thread_checker_.DetachFromThread(); }
 
    private:
     friend class base::RefCountedThreadSafe<Flag>;
 
     ~Flag();
 
-    SequenceChecker sequence_checker_;
+    ThreadChecker thread_checker_;
     bool is_valid_;
   };
 
diff --git a/base/message_loop/message_pump_io_ios.h b/base/message_loop/message_pump_io_ios.h
index 6779aab..6596862b 100644
--- a/base/message_loop/message_pump_io_ios.h
+++ b/base/message_loop/message_pump_io_ios.h
@@ -11,7 +11,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_pump_mac.h"
 #include "base/observer_list.h"
-#include "base/threading/thread_checker.h"
 
 namespace base {
 
diff --git a/base/sequence_checker.h b/base/sequence_checker.h
index 89bbd7e..fbf146a 100644
--- a/base/sequence_checker.h
+++ b/base/sequence_checker.h
@@ -28,11 +28,12 @@ class SequencedTaskRunner;
 // the right version for your build configuration.
 class SequenceCheckerDoNothing {
  public:
-  bool CalledOnValidSequencedThread() const {
+  bool CalledOnValidSequence() const {
     return true;
   }
 
-  void DetachFromSequence() {}
+  void ChangeSequence(
+      const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner) {}
 };
 
 // SequenceChecker is a helper class used to help verify that some
@@ -43,6 +44,10 @@ class SequenceCheckerDoNothing {
 // Example:
 // class MyClass {
 //  public:
+//   explicit MyClass(
+//       const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner)
+//       : sequence_checker_(sequenced_task_runner) {}
+//
 //   void Foo() {
 //     DCHECK(sequence_checker_.CalledOnValidSequence());
 //     ... (do stuff) ...
@@ -55,9 +60,16 @@ class SequenceCheckerDoNothing {
 // In Release mode, CalledOnValidSequence will always return true.
 #if ENABLE_SEQUENCE_CHECKER
 class SequenceChecker : public SequenceCheckerImpl {
+ public:
+  explicit SequenceChecker(
+      const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner)
+      : SequenceCheckerImpl(sequenced_task_runner) {}
 };
 #else
 class SequenceChecker : public SequenceCheckerDoNothing {
+ public:
+  explicit SequenceChecker(
+      const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner) {}
 };
 #endif  // ENABLE_SEQUENCE_CHECKER
 
diff --git a/base/sequence_checker_impl.cc b/base/sequence_checker_impl.cc
index e95b8ee..24d9ed9 100644
--- a/base/sequence_checker_impl.cc
+++ b/base/sequence_checker_impl.cc
@@ -4,43 +4,28 @@
 
 #include "base/sequence_checker_impl.h"
 
+#include "base/sequenced_task_runner.h"
+
 namespace base {
 
-SequenceCheckerImpl::SequenceCheckerImpl()
-    : sequence_token_assigned_(false) {
-  AutoLock auto_lock(lock_);
-  EnsureSequenceTokenAssigned();
-}
+SequenceCheckerImpl::SequenceCheckerImpl(
+    const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner)
+    : sequenced_task_runner_(sequenced_task_runner) {}
 
 SequenceCheckerImpl::~SequenceCheckerImpl() {}
 
-bool SequenceCheckerImpl::CalledOnValidSequencedThread() const {
+bool SequenceCheckerImpl::CalledOnValidSequence() const {
   AutoLock auto_lock(lock_);
-  EnsureSequenceTokenAssigned();
-
-  // If this thread is not associated with a SequencedWorkerPool,
-  // SequenceChecker behaves as a ThreadChecker. See header for details.
-  if (!sequence_token_.IsValid())
-    return thread_checker_.CalledOnValidThread();
-
-  return sequence_token_.Equals(
-      SequencedWorkerPool::GetSequenceTokenForCurrentThread());
+  return sequenced_task_runner_.get() ?
+      sequenced_task_runner_->RunsTasksOnCurrentThread() :
+      thread_checker_.CalledOnValidThread();
 }
 
-void SequenceCheckerImpl::DetachFromSequence() {
+void SequenceCheckerImpl::ChangeSequence(
+    const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner) {
   AutoLock auto_lock(lock_);
+  sequenced_task_runner_ = sequenced_task_runner;
   thread_checker_.DetachFromThread();
-  sequence_token_assigned_ = false;
-  sequence_token_ = SequencedWorkerPool::SequenceToken();
-}
-
-void SequenceCheckerImpl::EnsureSequenceTokenAssigned() const {
-  lock_.AssertAcquired();
-  if (sequence_token_assigned_)
-    return;
-
-  sequence_token_assigned_ = true;
-  sequence_token_ = SequencedWorkerPool::GetSequenceTokenForCurrentThread();
 }
 
 }  // namespace base
diff --git a/base/sequence_checker_impl.h b/base/sequence_checker_impl.h
index 741aafe..ccd1198 100644
--- a/base/sequence_checker_impl.h
+++ b/base/sequence_checker_impl.h
@@ -7,42 +7,48 @@
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
-#include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_checker_impl.h"
 
 namespace base {
 
+class SequencedTaskRunner;
+
 // SequenceCheckerImpl is used to help verify that some methods of a
 // class are called in sequence -- that is, called from the same
 // SequencedTaskRunner. It is a generalization of ThreadChecker; in
-// particular, it behaves exactly like ThreadChecker if constructed
-// on a thread that is not part of a SequencedWorkerPool.
+// particular, it behaves exactly like ThreadChecker if its passed a
+// NULL SequencedTaskRunner.
 class BASE_EXPORT SequenceCheckerImpl {
  public:
-  SequenceCheckerImpl();
+  // |sequenced_task_runner| can be NULL.  In that case, this object
+  // behaves exactly like a ThreadChecker bound to the current thread,
+  // i.e.  CalledOnValidSequence() behaves like CalledOnValidThread().
+  explicit SequenceCheckerImpl(
+      const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner);
   ~SequenceCheckerImpl();
 
-  // Returns whether the we are being called on the same sequence token
-  // as previous calls. If there is no associated sequence, then returns
-  // whether we are being called on the underlying ThreadChecker's thread.
-  bool CalledOnValidSequencedThread() const;
+  // Returns whether the we are being called on the underyling
+  // SequencedTaskRunner.  If we're not bound to a
+  // |sequenced_task_runner|, returns whether we are being called on
+  // the underlying ThreadChecker's thread.
+  bool CalledOnValidSequence() const;
 
-  // Unbinds the checker from the currently associated sequence. The
-  // checker will be re-bound on the next call to CalledOnValidSequence().
-  void DetachFromSequence();
+  // Changes the underyling SequencedTaskRunner.
+  // |sequenced_task_runner| can be NULL.  In that case, this object
+  // behaves exactly like a ThreadChecker that has been detached from
+  // its thread, i.e. we will be bound to the thread on which we next
+  // call CalledOnValidSequence().
+  void ChangeSequence(
+      const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner);
 
  private:
-  void EnsureSequenceTokenAssigned() const;
-
   // Guards all variables below.
   mutable Lock lock_;
-
-  // Used if |sequence_token_| is not valid.
+  scoped_refptr<SequencedTaskRunner> sequenced_task_runner_;
+  // Used if |sequenced_task_runner_| is NULL.
   ThreadCheckerImpl thread_checker_;
-  mutable bool sequence_token_assigned_;
-
-  mutable SequencedWorkerPool::SequenceToken sequence_token_;
 
   DISALLOW_COPY_AND_ASSIGN(SequenceCheckerImpl);
 };
diff --git a/base/sequence_checker_impl_unittest.cc b/base/sequence_checker_impl_unittest.cc
new file mode 100644
index 0000000..b05da11
--- /dev/null
+++ b/base/sequence_checker_impl_unittest.cc
@@ -0,0 +1,218 @@
+// Copyright 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 "base/sequence_checker_impl.h"
+
+#include <cstddef>
+
+#include "base/bind.h"
+#include "base/compiler_specific.h"
+#include "base/location.h"
+#include "base/memory/ref_counted.h"
+#include "base/message_loop/message_loop.h"
+#include "base/sequenced_task_runner.h"
+#include "base/threading/thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+namespace {
+
+// Implementation of SequencedTaskRunner that lets us control what
+// RunsTasksOnCurrentThread() returns.
+class FakeTaskRunner : public SequencedTaskRunner {
+ public:
+  FakeTaskRunner() : runs_tasks_on_current_thread_(false) {}
+
+  void SetRunsTasksOnCurrentThread(bool runs_tasks_on_current_thread) {
+    runs_tasks_on_current_thread_ = runs_tasks_on_current_thread;
+  }
+
+  // SequencedTaskRunner implementation.
+  virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
+                               const Closure& task,
+                               TimeDelta delay) OVERRIDE {
+    ADD_FAILURE();
+    return false;
+  }
+
+  virtual bool PostNonNestableDelayedTask(
+      const tracked_objects::Location& from_here,
+      const Closure& task,
+      TimeDelta delay) OVERRIDE {
+    ADD_FAILURE();
+    return false;
+  }
+
+  virtual bool RunsTasksOnCurrentThread() const OVERRIDE {
+    return runs_tasks_on_current_thread_;
+  }
+
+ protected:
+  virtual ~FakeTaskRunner() {}
+
+ private:
+  bool runs_tasks_on_current_thread_;
+};
+
+class SequenceCheckerImplTest : public ::testing::Test {
+};
+
+// Create a SequenceCheckerImpl with a SequencedTaskRunner and make
+// sure that CalledOnValidSequence() returns what that SequencedTaskRunner
+// returns for RunsTasksOnCurrentThread().
+TEST_F(SequenceCheckerImplTest, CalledOnValidSequenceNonNull) {
+  const scoped_refptr<FakeTaskRunner> fake_sequenced_task_runner(
+      new FakeTaskRunner());
+
+  const SequenceCheckerImpl sequence_checker_impl(fake_sequenced_task_runner);
+  EXPECT_FALSE(sequence_checker_impl.CalledOnValidSequence());
+
+  fake_sequenced_task_runner->SetRunsTasksOnCurrentThread(true);
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+
+  fake_sequenced_task_runner->SetRunsTasksOnCurrentThread(false);
+  EXPECT_FALSE(sequence_checker_impl.CalledOnValidSequence());
+}
+
+void ExpectCalledOnValidSequence(
+    const tracked_objects::Location& location,
+    const SequenceCheckerImpl* sequence_checker_impl,
+    bool expected_value) {
+  EXPECT_EQ(expected_value, sequence_checker_impl->CalledOnValidSequence())
+      << location.ToString();
+}
+
+// Create a SequenceCheckerImpl with no SequencedTaskRunner and make
+// sure that CalledOnValidSequence() behaves like
+// ThreadChecker::CalledOnValidThread().
+TEST_F(SequenceCheckerImplTest, CalledOnValidSequenceNull) {
+  const SequenceCheckerImpl sequence_checker_impl(NULL);
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+
+  {
+    Thread thread("thread 1");
+    ASSERT_TRUE(thread.Start());
+    thread.message_loop()->PostTask(
+        FROM_HERE, Bind(&ExpectCalledOnValidSequence,
+                        FROM_HERE,
+                        Unretained(&sequence_checker_impl),
+                        false));
+  }
+
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+}
+
+// Create a SequenceCheckerImpl with a SequencedTaskRunner and switch
+// it to another one. CalledOnValidSequence() should return what its
+// underlying SequencedTaskRunner returns for
+// RunsTasksOnCurrentThread().
+TEST_F(SequenceCheckerImplTest, ChangeSequenceNonNull) {
+  const scoped_refptr<FakeTaskRunner> fake_sequenced_task_runner1(
+      new FakeTaskRunner());
+
+  const scoped_refptr<FakeTaskRunner> fake_sequenced_task_runner2(
+      new FakeTaskRunner());
+
+  SequenceCheckerImpl sequence_checker_impl(fake_sequenced_task_runner1);
+  EXPECT_FALSE(sequence_checker_impl.CalledOnValidSequence());
+
+  fake_sequenced_task_runner2->SetRunsTasksOnCurrentThread(true);
+  EXPECT_FALSE(sequence_checker_impl.CalledOnValidSequence());
+
+  sequence_checker_impl.ChangeSequence(fake_sequenced_task_runner2);
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+
+  sequence_checker_impl.ChangeSequence(fake_sequenced_task_runner1);
+  EXPECT_FALSE(sequence_checker_impl.CalledOnValidSequence());
+}
+
+// Create a SequenceCheckerImpl with a SequencedTaskRunner and switch
+// it to a NULL one. CalledOnValidSequence() should then behave like
+// ThreadChecker::CalledOnValidThread().
+TEST_F(SequenceCheckerImplTest, ChangeSequenceNull) {
+  const scoped_refptr<FakeTaskRunner> fake_sequenced_task_runner(
+      new FakeTaskRunner());
+
+  SequenceCheckerImpl sequence_checker_impl(fake_sequenced_task_runner);
+  EXPECT_FALSE(sequence_checker_impl.CalledOnValidSequence());
+
+  sequence_checker_impl.ChangeSequence(NULL);
+  // Binds to current thread.
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+  {
+    Thread thread("thread 1");
+    ASSERT_TRUE(thread.Start());
+    thread.message_loop()->PostTask(
+        FROM_HERE, Bind(&ExpectCalledOnValidSequence,
+                        FROM_HERE,
+                        Unretained(&sequence_checker_impl),
+                        false));
+  }
+
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+
+  sequence_checker_impl.ChangeSequence(NULL);
+  // Binds to worker thread.
+  {
+    Thread thread("thread 2");
+    ASSERT_TRUE(thread.Start());
+    thread.message_loop()->PostTask(
+        FROM_HERE, Bind(&ExpectCalledOnValidSequence,
+                        FROM_HERE,
+                        Unretained(&sequence_checker_impl),
+                        true));
+  }
+  EXPECT_FALSE(sequence_checker_impl.CalledOnValidSequence());
+}
+
+// Create a SequenceCheckerImpl with the current thread's task runner
+// and switch it to other task runners. CalledOnValidSequence() should
+// return true only when it's on the correct thread.
+TEST_F(SequenceCheckerImplTest, MultipleThreads) {
+  MessageLoop loop;
+
+  SequenceCheckerImpl sequence_checker_impl(loop.message_loop_proxy());
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+
+  {
+    Thread thread("thread 1");
+    ASSERT_TRUE(thread.Start());
+    thread.message_loop()->PostTask(
+        FROM_HERE, Bind(&ExpectCalledOnValidSequence,
+                        FROM_HERE,
+                        Unretained(&sequence_checker_impl),
+                        false));
+    thread.message_loop()->PostTask(
+        FROM_HERE, Bind(&SequenceCheckerImpl::ChangeSequence,
+                        Unretained(&sequence_checker_impl),
+                        thread.message_loop_proxy()));
+    thread.message_loop()->PostTask(
+        FROM_HERE, Bind(&ExpectCalledOnValidSequence,
+                        FROM_HERE,
+                        Unretained(&sequence_checker_impl),
+                        true));
+  }
+
+  EXPECT_FALSE(sequence_checker_impl.CalledOnValidSequence());
+
+  sequence_checker_impl.ChangeSequence(loop.message_loop_proxy());
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+
+  {
+    Thread thread("thread 2");
+    ASSERT_TRUE(thread.Start());
+    thread.message_loop()->PostTask(
+        FROM_HERE, Bind(&ExpectCalledOnValidSequence,
+                        FROM_HERE,
+                        Unretained(&sequence_checker_impl),
+                        false));
+  }
+
+  EXPECT_TRUE(sequence_checker_impl.CalledOnValidSequence());
+}
+
+}  // namespace
+
+}  // namespace base
diff --git a/base/sequence_checker_unittest.cc b/base/sequence_checker_unittest.cc
index 7df7614..4fc3027 100644
--- a/base/sequence_checker_unittest.cc
+++ b/base/sequence_checker_unittest.cc
@@ -1,339 +1,29 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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 "base/basictypes.h"
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/location.h"
-#include "base/logging.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/message_loop/message_loop.h"
 #include "base/sequence_checker.h"
-#include "base/test/sequenced_worker_pool_owner.h"
-#include "base/threading/thread.h"
-#include "testing/gtest/include/gtest/gtest.h"
 
-// Duplicated from base/sequence_checker.h so that we can be good citizens
-// there and undef the macro.
-#if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
-#define ENABLE_SEQUENCE_CHECKER 1
-#else
-#define ENABLE_SEQUENCE_CHECKER 0
-#endif
+#include <cstddef>
+
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "base/test/null_task_runner.h"
+#include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
 namespace {
 
-const size_t kNumWorkerThreads = 3;
-
-// Simple class to exercise the basics of SequenceChecker.
-// DoStuff should verify that it's called on a valid sequenced thread.
-// SequenceCheckedObject can be destroyed on any thread (like WeakPtr).
-class SequenceCheckedObject {
- public:
-  SequenceCheckedObject() {}
-  ~SequenceCheckedObject() {}
-
-  // Verifies that it was called on the same thread as the constructor.
-  void DoStuff() {
-    DCHECK(sequence_checker_.CalledOnValidSequencedThread());
-  }
-
-  void DetachFromSequence() {
-    sequence_checker_.DetachFromSequence();
-  }
-
- private:
-  SequenceChecker sequence_checker_;
-
-  DISALLOW_COPY_AND_ASSIGN(SequenceCheckedObject);
-};
-
-class SequenceCheckerTest : public testing::Test {
- public:
-  SequenceCheckerTest() : other_thread_("sequence_checker_test_other_thread") {}
-
-  virtual ~SequenceCheckerTest() {}
-
-  virtual void SetUp() OVERRIDE {
-    other_thread_.Start();
-    ResetPool();
-  }
-
-  virtual void TearDown() OVERRIDE {
-    other_thread_.Stop();
-    pool()->Shutdown();
-  }
-
- protected:
-  base::Thread* other_thread() { return &other_thread_; }
-
-  const scoped_refptr<SequencedWorkerPool>& pool() {
-    return pool_owner_->pool();
-  }
-
-  void PostDoStuffToWorkerPool(SequenceCheckedObject* sequence_checked_object,
-                               const std::string& token_name) {
-    pool()->PostNamedSequencedWorkerTask(
-        token_name,
-        FROM_HERE,
-        base::Bind(&SequenceCheckedObject::DoStuff,
-                   base::Unretained(sequence_checked_object)));
-  }
-
-  void PostDoStuffToOtherThread(
-      SequenceCheckedObject* sequence_checked_object) {
-    other_thread()->message_loop()->PostTask(
-        FROM_HERE,
-        base::Bind(&SequenceCheckedObject::DoStuff,
-                   base::Unretained(sequence_checked_object)));
-  }
-
-  void PostDeleteToOtherThread(
-      scoped_ptr<SequenceCheckedObject> sequence_checked_object) {
-    other_thread()->message_loop()->DeleteSoon(
-        FROM_HERE,
-        sequence_checked_object.release());
-  }
-
-  // Destroys the SequencedWorkerPool instance, blocking until it is fully shut
-  // down, and creates a new instance.
-  void ResetPool() {
-    pool_owner_.reset(new SequencedWorkerPoolOwner(kNumWorkerThreads, "test"));
-  }
-
-  void MethodOnDifferentThreadDeathTest();
-  void DetachThenCallFromDifferentThreadDeathTest();
-  void DifferentSequenceTokensDeathTest();
-  void WorkerPoolAndSimpleThreadDeathTest();
-  void TwoDifferentWorkerPoolsDeathTest();
-
- private:
-  MessageLoop message_loop_;  // Needed by SequencedWorkerPool to function.
-  base::Thread other_thread_;
-  scoped_ptr<SequencedWorkerPoolOwner> pool_owner_;
-};
-
-TEST_F(SequenceCheckerTest, CallsAllowedOnSameThread) {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  // Verify that DoStuff doesn't assert.
-  sequence_checked_object->DoStuff();
-
-  // Verify that the destructor doesn't assert.
-  sequence_checked_object.reset();
-}
-
-TEST_F(SequenceCheckerTest, DestructorAllowedOnDifferentThread) {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  // Verify the destructor doesn't assert when called on a different thread.
-  PostDeleteToOtherThread(sequence_checked_object.Pass());
-  other_thread()->Stop();
-}
-
-TEST_F(SequenceCheckerTest, DetachFromSequence) {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  // Verify that DoStuff doesn't assert when called on a different thread after
-  // a call to DetachFromSequence.
-  sequence_checked_object->DetachFromSequence();
-
-  PostDoStuffToOtherThread(sequence_checked_object.get());
-  other_thread()->Stop();
-}
-
-TEST_F(SequenceCheckerTest, SameSequenceTokenValid) {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  sequence_checked_object->DetachFromSequence();
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  pool()->FlushForTesting();
-
-  PostDeleteToOtherThread(sequence_checked_object.Pass());
-  other_thread()->Stop();
-}
-
-TEST_F(SequenceCheckerTest, DetachSequenceTokenValid) {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  sequence_checked_object->DetachFromSequence();
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  pool()->FlushForTesting();
-
-  sequence_checked_object->DetachFromSequence();
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "B");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "B");
-  pool()->FlushForTesting();
-
-  PostDeleteToOtherThread(sequence_checked_object.Pass());
-  other_thread()->Stop();
-}
-
-#if GTEST_HAS_DEATH_TEST || !ENABLE_SEQUENCE_CHECKER
-
-void SequenceCheckerTest::MethodOnDifferentThreadDeathTest() {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  // DoStuff should assert in debug builds only when called on a
-  // different thread.
-  PostDoStuffToOtherThread(sequence_checked_object.get());
-  other_thread()->Stop();
-}
-
-#if ENABLE_SEQUENCE_CHECKER
-TEST_F(SequenceCheckerTest, MethodNotAllowedOnDifferentThreadDeathTestInDebug) {
-  // The default style "fast" does not support multi-threaded tests.
-  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
-  ASSERT_DEATH({
-    MethodOnDifferentThreadDeathTest();
-  }, "");
-}
-#else
-TEST_F(SequenceCheckerTest, MethodAllowedOnDifferentThreadDeathTestInRelease) {
-  MethodOnDifferentThreadDeathTest();
-}
-#endif  // ENABLE_SEQUENCE_CHECKER
-
-void SequenceCheckerTest::DetachThenCallFromDifferentThreadDeathTest() {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  // DoStuff doesn't assert when called on a different thread
-  // after a call to DetachFromSequence.
-  sequence_checked_object->DetachFromSequence();
-  PostDoStuffToOtherThread(sequence_checked_object.get());
-  other_thread()->Stop();
-
-  // DoStuff should assert in debug builds only after moving to
-  // another thread.
-  sequence_checked_object->DoStuff();
-}
-
-#if ENABLE_SEQUENCE_CHECKER
-TEST_F(SequenceCheckerTest, DetachFromSequenceDeathTestInDebug) {
-  // The default style "fast" does not support multi-threaded tests.
-  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
-  ASSERT_DEATH({
-    DetachThenCallFromDifferentThreadDeathTest();
-  }, "");
-}
-#else
-TEST_F(SequenceCheckerTest, DetachFromThreadDeathTestInRelease) {
-  DetachThenCallFromDifferentThreadDeathTest();
-}
-#endif  // ENABLE_SEQUENCE_CHECKER
-
-void SequenceCheckerTest::DifferentSequenceTokensDeathTest() {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  sequence_checked_object->DetachFromSequence();
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "B");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "B");
-  pool()->FlushForTesting();
-
-  PostDeleteToOtherThread(sequence_checked_object.Pass());
-  other_thread()->Stop();
+// Call various methods of SequenceChecker to make sure nothing blows
+// up in either debug or release mode.
+TEST(SequenceCheckerTest, Basic) {
+  SequenceChecker sequence_checker(new NullTaskRunner());
+  sequence_checker.CalledOnValidSequence();
+  sequence_checker.ChangeSequence(NULL);
+  sequence_checker.CalledOnValidSequence();
 }
 
-#if ENABLE_SEQUENCE_CHECKER
-TEST_F(SequenceCheckerTest, DifferentSequenceTokensDeathTestInDebug) {
-  // The default style "fast" does not support multi-threaded tests.
-  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
-  ASSERT_DEATH({
-    DifferentSequenceTokensDeathTest();
-  }, "");
-}
-#else
-TEST_F(SequenceCheckerTest,
-     DifferentSequenceTokensDeathTestInRelease) {
-  DifferentSequenceTokensDeathTest();
-}
-#endif  // ENABLE_SEQUENCE_CHECKER
-
-void SequenceCheckerTest::WorkerPoolAndSimpleThreadDeathTest() {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  sequence_checked_object->DetachFromSequence();
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  pool()->FlushForTesting();
-
-  PostDoStuffToOtherThread(sequence_checked_object.get());
-  other_thread()->Stop();
-}
-
-#if ENABLE_SEQUENCE_CHECKER
-TEST_F(SequenceCheckerTest, WorkerPoolAndSimpleThreadDeathTestInDebug) {
-  // The default style "fast" does not support multi-threaded tests.
-  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
-  ASSERT_DEATH({
-    WorkerPoolAndSimpleThreadDeathTest();
-  }, "");
-}
-#else
-TEST_F(SequenceCheckerTest,
-     WorkerPoolAndSimpleThreadDeathTestInRelease) {
-  WorkerPoolAndSimpleThreadDeathTest();
-}
-#endif  // ENABLE_SEQUENCE_CHECKER
-
-void SequenceCheckerTest::TwoDifferentWorkerPoolsDeathTest() {
-  scoped_ptr<SequenceCheckedObject> sequence_checked_object(
-      new SequenceCheckedObject);
-
-  sequence_checked_object->DetachFromSequence();
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  PostDoStuffToWorkerPool(sequence_checked_object.get(), "A");
-  pool()->FlushForTesting();
-
-  SequencedWorkerPoolOwner second_pool_owner(kNumWorkerThreads, "test2");
-  second_pool_owner.pool()->PostNamedSequencedWorkerTask(
-      "A",
-      FROM_HERE,
-      base::Bind(&SequenceCheckedObject::DoStuff,
-                 base::Unretained(sequence_checked_object.get())));
-  second_pool_owner.pool()->FlushForTesting();
-  second_pool_owner.pool()->Shutdown();
-}
-
-#if ENABLE_SEQUENCE_CHECKER
-TEST_F(SequenceCheckerTest, TwoDifferentWorkerPoolsDeathTestInDebug) {
-  // The default style "fast" does not support multi-threaded tests.
-  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
-  ASSERT_DEATH({
-    TwoDifferentWorkerPoolsDeathTest();
-  }, "");
-}
-#else
-TEST_F(SequenceCheckerTest,
-     TwoDifferentWorkerPoolsDeathTestInRelease) {
-  TwoDifferentWorkerPoolsDeathTest();
-}
-#endif  // ENABLE_SEQUENCE_CHECKER
-
-#endif  // GTEST_HAS_DEATH_TEST || !ENABLE_SEQUENCE_CHECKER
-
 }  // namespace
 
 }  // namespace base
-
-// Just in case we ever get lumped together with other compilation units.
-#undef ENABLE_SEQUENCE_CHECKER
diff --git a/chrome/browser/storage_monitor/storage_monitor.h b/chrome/browser/storage_monitor/storage_monitor.h
index 5c0cd96..9d20d60 100644
--- a/chrome/browser/storage_monitor/storage_monitor.h
+++ b/chrome/browser/storage_monitor/storage_monitor.h
@@ -14,7 +14,6 @@
 #include "base/observer_list_threadsafe.h"
 #include "base/strings/string16.h"
 #include "base/synchronization/lock.h"
-#include "base/threading/thread_checker.h"
 #include "chrome/browser/storage_monitor/storage_info.h"
 
 class ChromeBrowserMainPartsLinux;
diff --git a/content/renderer/media/webmediaplayer_ms.h b/content/renderer/media/webmediaplayer_ms.h
index fae271b..106e0bc 100644
--- a/content/renderer/media/webmediaplayer_ms.h
+++ b/content/renderer/media/webmediaplayer_ms.h
@@ -9,7 +9,6 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
-#include "base/threading/thread_checker.h"
 #include "cc/layers/video_frame_provider.h"
 #include "media/filters/skcanvas_video_renderer.h"
 #include "skia/ext/platform_canvas.h"
diff --git a/remoting/host/audio_capturer_win.h b/remoting/host/audio_capturer_win.h
index 1a7ddad..c871bca 100644
--- a/remoting/host/audio_capturer_win.h
+++ b/remoting/host/audio_capturer_win.h
@@ -10,7 +10,6 @@
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "base/win/scoped_co_mem.h"
 #include "base/win/scoped_comptr.h"
diff --git a/tools/valgrind/gtest_exclude/base_unittests.gtest.txt b/tools/valgrind/gtest_exclude/base_unittests.gtest.txt
index 35c209d..8270720 100644
--- a/tools/valgrind/gtest_exclude/base_unittests.gtest.txt
+++ b/tools/valgrind/gtest_exclude/base_unittests.gtest.txt
@@ -24,3 +24,7 @@ ConditionVariableTest.LargeFastTaskTest
 
 # Flaky under Valgrind, see http://crbug.com/55517
 PlatformFile.TouchGetInfoPlatformFile
+
+# Death test crashes with NULL deref, probably not intended.
+# http://crbug.com/261141
+SequenceCheckerTest.*DeathTest*