diff --git a/webrtc/modules/audio_device/test/audio_device_test_api.cc b/webrtc/modules/audio_device/test/audio_device_test_api.cc
index b4b8235d0..09f70bd85 100644
--- a/webrtc/modules/audio_device/test/audio_device_test_api.cc
+++ b/webrtc/modules/audio_device/test/audio_device_test_api.cc
@@ -166,7 +166,7 @@ class AudioDeviceAPITest: public testing::Test {
   virtual ~AudioDeviceAPITest() {}
 
   static void SetUpTestCase() {
-    process_thread_ = ProcessThread::CreateProcessThread();
+    process_thread_ = ProcessThread::Create();
     process_thread_->Start();
 
     // Windows:
@@ -274,7 +274,7 @@ class AudioDeviceAPITest: public testing::Test {
     if (process_thread_) {
       process_thread_->DeRegisterModule(audio_device_);
       process_thread_->Stop();
-      ProcessThread::DestroyProcessThread(process_thread_);
+      process_thread_.reset();
     }
     if (event_observer_) {
       delete event_observer_;
@@ -324,8 +324,9 @@ class AudioDeviceAPITest: public testing::Test {
     EXPECT_FALSE(audio_device_->MicrophoneIsInitialized());
   }
 
+  // TODO(henrika): Get rid of globals.
   static bool linux_alsa_;
-  static ProcessThread* process_thread_;
+  static rtc::scoped_ptr<ProcessThread> process_thread_;
   static AudioDeviceModule* audio_device_;
   static AudioTransportAPI* audio_transport_;
   static AudioEventObserverAPI* event_observer_;
@@ -333,7 +334,7 @@ class AudioDeviceAPITest: public testing::Test {
 
 // Must be initialized like this to handle static SetUpTestCase() above.
 bool AudioDeviceAPITest::linux_alsa_ = false;
-ProcessThread* AudioDeviceAPITest::process_thread_ = NULL;
+rtc::scoped_ptr<ProcessThread> AudioDeviceAPITest::process_thread_;
 AudioDeviceModule* AudioDeviceAPITest::audio_device_ = NULL;
 AudioTransportAPI* AudioDeviceAPITest::audio_transport_ = NULL;
 AudioEventObserverAPI* AudioDeviceAPITest::event_observer_ = NULL;
diff --git a/webrtc/modules/audio_device/test/func_test_manager.cc b/webrtc/modules/audio_device/test/func_test_manager.cc
index 3599873f3..d6e5cb3d9 100644
--- a/webrtc/modules/audio_device/test/func_test_manager.cc
+++ b/webrtc/modules/audio_device/test/func_test_manager.cc
@@ -558,7 +558,6 @@ void AudioTransportImpl::PullRenderData(int bits_per_sample, int sample_rate,
                                         int64_t* ntp_time_ms) {}
 
 FuncTestManager::FuncTestManager() :
-    _processThread(NULL),
     _audioDevice(NULL),
     _audioEventObserver(NULL),
     _audioTransport(NULL)
@@ -579,7 +578,7 @@ FuncTestManager::~FuncTestManager()
 
 int32_t FuncTestManager::Init()
 {
-    EXPECT_TRUE((_processThread = ProcessThread::CreateProcessThread()) != NULL);
+    EXPECT_TRUE((_processThread = ProcessThread::Create()) != NULL);
     if (_processThread == NULL)
     {
         return -1;
@@ -620,7 +619,7 @@ int32_t FuncTestManager::Close()
     {
         _processThread->DeRegisterModule(_audioDevice);
         _processThread->Stop();
-        ProcessThread::DestroyProcessThread(_processThread);
+        _processThread.reset();
     }
 
     // delete the audio observer
@@ -789,7 +788,7 @@ int32_t FuncTestManager::TestAudioLayerSelection()
         {
             _processThread->DeRegisterModule(_audioDevice);
             _processThread->Stop();
-            ProcessThread::DestroyProcessThread(_processThread);
+            _processThread.reset();
         }
 
         // delete the audio observer
@@ -816,7 +815,7 @@ int32_t FuncTestManager::TestAudioLayerSelection()
         // ==================================================
         // Next, try to make fresh start with new audio layer
 
-        EXPECT_TRUE((_processThread = ProcessThread::CreateProcessThread()) != NULL);
+        EXPECT_TRUE((_processThread = ProcessThread::Create()) != NULL);
         if (_processThread == NULL)
         {
             return -1;
diff --git a/webrtc/modules/audio_device/test/func_test_manager.h b/webrtc/modules/audio_device/test/func_test_manager.h
index 5cb4f4610..3c80cdc4a 100644
--- a/webrtc/modules/audio_device/test/func_test_manager.h
+++ b/webrtc/modules/audio_device/test/func_test_manager.h
@@ -245,7 +245,7 @@ private:
     std::string _playoutFile16;
     std::string _playoutFile8;
 
-    ProcessThread* _processThread;
+    rtc::scoped_ptr<ProcessThread> _processThread;
     AudioDeviceModule* _audioDevice;
     AudioEventObserver* _audioEventObserver;
     AudioTransportImpl* _audioTransport;
diff --git a/webrtc/modules/interface/module.h b/webrtc/modules/interface/module.h
index c3e303039..dfa1ad4e7 100644
--- a/webrtc/modules/interface/module.h
+++ b/webrtc/modules/interface/module.h
@@ -21,6 +21,11 @@ class Module {
   // thread to call Process.
   // This method is called on the same worker thread as Process will
   // be called on.
+  // TODO(tommi): Almost all implementations of this function, need to know
+  // the current tick count.  Consider passing it as an argument.  It could
+  // also improve the accuracy of when the next callback occurs since the
+  // thread that calls Process() will also have it's tick count reference
+  // which might not match with what the implementations use.
   virtual int64_t TimeUntilNextProcess() = 0;
 
   // Process any pending tasks such as timeouts.
diff --git a/webrtc/modules/modules.gyp b/webrtc/modules/modules.gyp
index 376e6c5b4..4a92d21f3 100644
--- a/webrtc/modules/modules.gyp
+++ b/webrtc/modules/modules.gyp
@@ -254,6 +254,7 @@
             'rtp_rtcp/test/testAPI/test_api_video.cc',
             'utility/source/audio_frame_operations_unittest.cc',
             'utility/source/file_player_unittests.cc',
+            'utility/source/process_thread_impl_unittest.cc',
             'video_coding/codecs/test/packet_manipulator_unittest.cc',
             'video_coding/codecs/test/stats_unittest.cc',
             'video_coding/codecs/test/videoprocessor_unittest.cc',
diff --git a/webrtc/modules/utility/interface/mock/mock_process_thread.h b/webrtc/modules/utility/interface/mock/mock_process_thread.h
index fc0c1fb1c..a181812f9 100644
--- a/webrtc/modules/utility/interface/mock/mock_process_thread.h
+++ b/webrtc/modules/utility/interface/mock/mock_process_thread.h
@@ -21,6 +21,7 @@ class MockProcessThread : public ProcessThread {
  public:
   MOCK_METHOD0(Start, int32_t());
   MOCK_METHOD0(Stop, int32_t());
+  MOCK_METHOD1(WakeUp, void(Module* module));
   MOCK_METHOD1(RegisterModule, int32_t(Module* module));
   MOCK_METHOD1(DeRegisterModule, int32_t(const Module* module));
 };
diff --git a/webrtc/modules/utility/interface/process_thread.h b/webrtc/modules/utility/interface/process_thread.h
index 4db92a308..2262f2d7a 100644
--- a/webrtc/modules/utility/interface/process_thread.h
+++ b/webrtc/modules/utility/interface/process_thread.h
@@ -12,23 +12,39 @@
 #define WEBRTC_MODULES_UTILITY_INTERFACE_PROCESS_THREAD_H_
 
 #include "webrtc/typedefs.h"
+#include "webrtc/base/scoped_ptr.h"
 
 namespace webrtc {
 class Module;
 
-class ProcessThread
-{
-public:
-    static ProcessThread* CreateProcessThread();
-    static void DestroyProcessThread(ProcessThread* module);
+class ProcessThread {
+ public:
+  virtual ~ProcessThread();
 
-    virtual int32_t Start() = 0;
-    virtual int32_t Stop() = 0;
+  static rtc::scoped_ptr<ProcessThread> Create();
 
-    virtual int32_t RegisterModule(Module* module) = 0;
-    virtual int32_t DeRegisterModule(const Module* module) = 0;
-protected:
-    virtual ~ProcessThread();
+  // Starts the worker thread.  Must be called from the construction thread.
+  virtual int32_t Start() = 0;
+
+  // Stops the worker thread.  Must be called from the construction thread.
+  virtual int32_t Stop() = 0;
+
+  // Wakes the thread up to give a module a chance to do processing right
+  // away.  This causes the worker thread to wake up and requery the specified
+  // module for when it should be called back. (Typically the module should
+  // return 0 from TimeUntilNextProcess on the worker thread at that point).
+  // Can be called on any thread.
+  virtual void WakeUp(Module* module) = 0;
+
+  // Adds a module that will start to receive callbacks on the worker thread.
+  // Can be called from any thread.
+  virtual int32_t RegisterModule(Module* module) = 0;
+
+  // Removes a previously registered module.
+  // Can be called from any thread.
+  virtual int32_t DeRegisterModule(const Module* module) = 0;
 };
+
 }  // namespace webrtc
+
 #endif // WEBRTC_MODULES_UTILITY_INTERFACE_PROCESS_THREAD_H_
diff --git a/webrtc/modules/utility/source/process_thread_impl.cc b/webrtc/modules/utility/source/process_thread_impl.cc
index e2e9542c7..9b13daa2b 100644
--- a/webrtc/modules/utility/source/process_thread_impl.cc
+++ b/webrtc/modules/utility/source/process_thread_impl.cc
@@ -8,163 +8,161 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/modules/interface/module.h"
 #include "webrtc/modules/utility/source/process_thread_impl.h"
 
+#include "webrtc/base/checks.h"
+#include "webrtc/modules/interface/module.h"
+#include "webrtc/system_wrappers/interface/logging.h"
+#include "webrtc/system_wrappers/interface/tick_util.h"
 
 namespace webrtc {
-ProcessThread::~ProcessThread()
-{
+namespace {
+int64_t GetNextCallbackTime(Module* module, int64_t time_now) {
+  int64_t interval = module->TimeUntilNextProcess();
+  // Currently some implementations erroneously return error codes from
+  // TimeUntilNextProcess(). So, as is, we correct that and log an error.
+  if (interval < 0) {
+    LOG(LS_ERROR) << "TimeUntilNextProcess returned an invalid value "
+                  << interval;
+    interval = 0;
+  }
+  return time_now + interval;
+}
 }
 
-ProcessThread* ProcessThread::CreateProcessThread()
-{
-    return new ProcessThreadImpl();
-}
+ProcessThread::~ProcessThread() {}
 
-void ProcessThread::DestroyProcessThread(ProcessThread* module)
-{
-    delete module;
+// static
+rtc::scoped_ptr<ProcessThread> ProcessThread::Create() {
+  return rtc::scoped_ptr<ProcessThread>(new ProcessThreadImpl()).Pass();
 }
 
 ProcessThreadImpl::ProcessThreadImpl()
-    : _timeEvent(*EventWrapper::Create()),
-      _critSectModules(CriticalSectionWrapper::CreateCriticalSection()),
-      _thread(NULL)
-{
+    : wake_up_(EventWrapper::Create()), stop_(false) {
 }
 
-ProcessThreadImpl::~ProcessThreadImpl()
-{
-    delete _critSectModules;
-    delete &_timeEvent;
+ProcessThreadImpl::~ProcessThreadImpl() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!thread_.get());
+  DCHECK(!stop_);
 }
 
-int32_t ProcessThreadImpl::Start()
-{
-    CriticalSectionScoped lock(_critSectModules);
-    if(_thread)
-    {
-        return -1;
-    }
-    _thread = ThreadWrapper::CreateThread(Run, this, kNormalPriority,
-                                          "ProcessThread");
-    unsigned int id;
-    int32_t retVal = _thread->Start(id);
-    if(retVal >= 0)
-    {
-        return 0;
-    }
-    delete _thread;
-    _thread = NULL;
+int32_t ProcessThreadImpl::Start() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (thread_.get())
     return -1;
+
+  DCHECK(!stop_);
+
+  thread_.reset(ThreadWrapper::CreateThread(
+      &ProcessThreadImpl::Run, this, kNormalPriority, "ProcessThread"));
+  unsigned int id;
+  if (!thread_->Start(id)) {
+    thread_.reset();
+    return -1;
+  }
+
+  return 0;
 }
 
-int32_t ProcessThreadImpl::Stop()
-{
-    _critSectModules->Enter();
-    if(_thread)
-    {
-        ThreadWrapper* thread = _thread;
-        _thread = NULL;
-
-        _timeEvent.Set();
-        _critSectModules->Leave();
-
-        if(thread->Stop())
-        {
-            delete thread;
-        } else {
-            return -1;
-        }
-    } else {
-        _critSectModules->Leave();
-    }
+int32_t ProcessThreadImpl::Stop() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if(!thread_.get())
     return 0;
+
+  {
+    rtc::CritScope lock(&lock_);
+    stop_ = true;
+  }
+
+  wake_up_->Set();
+
+  thread_->Stop();
+  thread_.reset();
+  stop_ = false;
+
+  return 0;
 }
 
-int32_t ProcessThreadImpl::RegisterModule(Module* module)
-{
-    CriticalSectionScoped lock(_critSectModules);
+void ProcessThreadImpl::WakeUp(Module* module) {
+  // Allowed to be called on any thread.
+  {
+    rtc::CritScope lock(&lock_);
+    ModuleCallback cb(module);
+    const auto& found = std::find(modules_.begin(), modules_.end(), cb);
+    DCHECK(found != modules_.end()) << "programmer error?";
+    (*found).next_callback = 0;
+  }
+  wake_up_->Set();
+}
+
+int32_t ProcessThreadImpl::RegisterModule(Module* module) {
+  // Allowed to be called on any thread.
+  {
+    rtc::CritScope lock(&lock_);
 
     // Only allow module to be registered once.
-    for (ModuleList::iterator iter = _modules.begin();
-         iter != _modules.end(); ++iter) {
-        if(module == *iter)
-        {
-            return -1;
-        }
-    }
+    ModuleCallback cb(module);
+    if (std::find(modules_.begin(), modules_.end(), cb) != modules_.end())
+      return -1;
+    modules_.push_front(cb);
+  }
 
-    _modules.push_front(module);
+  // Wake the thread calling ProcessThreadImpl::Process() to update the
+  // waiting time. The waiting time for the just registered module may be
+  // shorter than all other registered modules.
+  wake_up_->Set();
 
-    // Wake the thread calling ProcessThreadImpl::Process() to update the
-    // waiting time. The waiting time for the just registered module may be
-    // shorter than all other registered modules.
-    _timeEvent.Set();
-    return 0;
+  return 0;
 }
 
-int32_t ProcessThreadImpl::DeRegisterModule(const Module* module)
-{
-    CriticalSectionScoped lock(_critSectModules);
-    for (ModuleList::iterator iter = _modules.begin();
-         iter != _modules.end(); ++iter) {
-        if(module == *iter)
-        {
-            _modules.erase(iter);
-            return 0;
-        }
-    }
-    return -1;
+int32_t ProcessThreadImpl::DeRegisterModule(const Module* module) {
+  // Allowed to be called on any thread.
+  rtc::CritScope lock(&lock_);
+  modules_.remove_if([&module](const ModuleCallback& m) {
+      return m.module == module;
+    });
+  return 0;
 }
 
-bool ProcessThreadImpl::Run(void* obj)
-{
-    return static_cast<ProcessThreadImpl*>(obj)->Process();
+// static
+bool ProcessThreadImpl::Run(void* obj) {
+  return static_cast<ProcessThreadImpl*>(obj)->Process();
 }
 
-bool ProcessThreadImpl::Process()
-{
-    // Wait for the module that should be called next, but don't block thread
-    // longer than 100 ms.
-    int64_t minTimeToNext = 100;
-    {
-        CriticalSectionScoped lock(_critSectModules);
-        for (ModuleList::iterator iter = _modules.begin();
-             iter != _modules.end(); ++iter) {
-          int64_t timeToNext = (*iter)->TimeUntilNextProcess();
-            if(minTimeToNext > timeToNext)
-            {
-                minTimeToNext = timeToNext;
-            }
-        }
-    }
+bool ProcessThreadImpl::Process() {
+  int64_t now = TickTime::MillisecondTimestamp();
+  int64_t next_checkpoint = now + (1000 * 60);
+  {
+    rtc::CritScope lock(&lock_);
+    if (stop_)
+      return false;
+    for (auto& m : modules_) {
+      // TODO(tommi): Would be good to measure the time TimeUntilNextProcess
+      // takes and dcheck if it takes too long (e.g. >=10ms).  Ideally this
+      // operation should not require taking a lock, so querying all modules
+      // should run in a matter of nanoseconds.
+      if (m.next_callback == 0)
+        m.next_callback = GetNextCallbackTime(m.module, now);
 
-    if(minTimeToNext > 0)
-    {
-        if(kEventError ==
-           _timeEvent.Wait(static_cast<unsigned long>(minTimeToNext)))
-        {
-            return true;
-        }
-        CriticalSectionScoped lock(_critSectModules);
-        if(!_thread)
-        {
-            return false;
-        }
+      if (m.next_callback <= now) {
+        m.module->Process();
+        // Use a new 'now' reference to calculate when the next callback
+        // should occur.  We'll continue to use 'now' above for the baseline
+        // of calculating how long we should wait, to reduce variance.
+        auto new_now = TickTime::MillisecondTimestamp();
+        m.next_callback = GetNextCallbackTime(m.module, new_now);
+      }
+
+      if (m.next_callback < next_checkpoint)
+        next_checkpoint = m.next_callback;
     }
-    {
-        CriticalSectionScoped lock(_critSectModules);
-        for (ModuleList::iterator iter = _modules.begin();
-             iter != _modules.end(); ++iter) {
-          int64_t timeToNext = (*iter)->TimeUntilNextProcess();
-            if(timeToNext < 1)
-            {
-                (*iter)->Process();
-            }
-        }
-    }
-    return true;
+  }
+
+  auto time_to_wait = next_checkpoint - TickTime::MillisecondTimestamp();
+  if (time_to_wait > 0)
+    wake_up_->Wait(static_cast<unsigned long>(time_to_wait));
+
+  return true;
 }
 }  // namespace webrtc
diff --git a/webrtc/modules/utility/source/process_thread_impl.h b/webrtc/modules/utility/source/process_thread_impl.h
index 14fbc18a2..5a42140fa 100644
--- a/webrtc/modules/utility/source/process_thread_impl.h
+++ b/webrtc/modules/utility/source/process_thread_impl.h
@@ -13,37 +13,52 @@
 
 #include <list>
 
+#include "webrtc/base/criticalsection.h"
+#include "webrtc/base/thread_checker.h"
 #include "webrtc/modules/utility/interface/process_thread.h"
-#include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
 #include "webrtc/system_wrappers/interface/event_wrapper.h"
 #include "webrtc/system_wrappers/interface/thread_wrapper.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
-class ProcessThreadImpl : public ProcessThread
-{
-public:
-    ProcessThreadImpl();
-    virtual ~ProcessThreadImpl();
 
-    virtual int32_t Start();
-    virtual int32_t Stop();
+class ProcessThreadImpl : public ProcessThread {
+ public:
+  ProcessThreadImpl();
+  ~ProcessThreadImpl() override;
 
-    virtual int32_t RegisterModule(Module* module);
-    virtual int32_t DeRegisterModule(const Module* module);
+  int32_t Start() override;
+  int32_t Stop() override;
 
-protected:
-    static bool Run(void* obj);
+  void WakeUp(Module* module) override;
 
-    bool Process();
+  int32_t RegisterModule(Module* module);
+  int32_t DeRegisterModule(const Module* module);
 
-private:
-    typedef std::list<Module*> ModuleList;
-    EventWrapper&           _timeEvent;
-    CriticalSectionWrapper* _critSectModules;
-    ModuleList              _modules;
-    ThreadWrapper*          _thread;
+ protected:
+  static bool Run(void* obj);
+  bool Process();
+
+ private:
+  rtc::ThreadChecker thread_checker_;
+  const rtc::scoped_ptr<EventWrapper> wake_up_;
+  rtc::scoped_ptr<ThreadWrapper> thread_;
+
+  struct ModuleCallback {
+    ModuleCallback(Module* module) : module(module), next_callback(0) {}
+    bool operator==(const ModuleCallback& cb) const {
+      return cb.module == module;
+    }
+    Module* const module;
+    int64_t next_callback;  // Absolute timestamp.
+  };
+
+  rtc::CriticalSection lock_;  // Used to guard modules_ and stop_.
+  typedef std::list<ModuleCallback> ModuleList;
+  ModuleList modules_;
+  bool stop_;
 };
+
 }  // namespace webrtc
 
 #endif // WEBRTC_MODULES_UTILITY_SOURCE_PROCESS_THREAD_IMPL_H_
diff --git a/webrtc/modules/utility/source/process_thread_impl_unittest.cc b/webrtc/modules/utility/source/process_thread_impl_unittest.cc
new file mode 100644
index 000000000..883554151
--- /dev/null
+++ b/webrtc/modules/utility/source/process_thread_impl_unittest.cc
@@ -0,0 +1,245 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/modules/interface/module.h"
+#include "webrtc/modules/utility/source/process_thread_impl.h"
+#include "webrtc/system_wrappers/interface/tick_util.h"
+
+namespace webrtc {
+
+using ::testing::_;
+using ::testing::DoAll;
+using ::testing::InSequence;
+using ::testing::Invoke;
+using ::testing::Return;
+using ::testing::SetArgPointee;
+
+class MockModule : public Module {
+ public:
+  MOCK_METHOD0(TimeUntilNextProcess, int64_t());
+  MOCK_METHOD0(Process, int32_t());
+};
+
+ACTION_P(SetEvent, event) {
+  event->Set();
+}
+
+ACTION_P(Increment, counter) {
+  ++(*counter);
+}
+
+ACTION_P(SetTimestamp, ptr) {
+  *ptr = TickTime::MillisecondTimestamp();
+}
+
+TEST(ProcessThreadImpl, StartStop) {
+  ProcessThreadImpl thread;
+  EXPECT_EQ(0, thread.Start());
+  EXPECT_EQ(0, thread.Stop());
+}
+
+TEST(ProcessThreadImpl, MultipleStartStop) {
+  ProcessThreadImpl thread;
+  for (int i = 0; i < 5; ++i) {
+    EXPECT_EQ(0, thread.Start());
+    EXPECT_EQ(0, thread.Stop());
+  }
+}
+
+// Verifies that we get at least call back to Process() on the worker thread.
+TEST(ProcessThreadImpl, ProcessCall) {
+  ProcessThreadImpl thread;
+  ASSERT_EQ(0, thread.Start());
+
+  rtc::scoped_ptr<EventWrapper> event(EventWrapper::Create());
+
+  MockModule module;
+  EXPECT_CALL(module, TimeUntilNextProcess()).WillRepeatedly(Return(0));
+  EXPECT_CALL(module, Process())
+      .WillOnce(DoAll(SetEvent(event.get()), Return(0)))
+      .WillRepeatedly(Return(0));
+
+  ASSERT_EQ(0, thread.RegisterModule(&module));
+  EXPECT_EQ(kEventSignaled, event->Wait(100));
+  EXPECT_EQ(0, thread.Stop());
+}
+
+// Same as ProcessCall except the module is registered before the
+// call to Start().
+TEST(ProcessThreadImpl, ProcessCall2) {
+  ProcessThreadImpl thread;
+  rtc::scoped_ptr<EventWrapper> event(EventWrapper::Create());
+
+  MockModule module;
+  EXPECT_CALL(module, TimeUntilNextProcess()).WillRepeatedly(Return(0));
+  EXPECT_CALL(module, Process())
+      .WillOnce(DoAll(SetEvent(event.get()), Return(0)))
+      .WillRepeatedly(Return(0));
+
+  ASSERT_EQ(0, thread.RegisterModule(&module));
+  ASSERT_EQ(thread.Start(), 0);
+  EXPECT_EQ(kEventSignaled, event->Wait(100));
+  EXPECT_EQ(thread.Stop(), 0);
+}
+
+// Tests setting up a module for callbacks and then unregister that module.
+// After unregistration, we should not receive any further callbacks.
+TEST(ProcessThreadImpl, Deregister) {
+  ProcessThreadImpl thread;
+  rtc::scoped_ptr<EventWrapper> event(EventWrapper::Create());
+
+  int process_count = 0;
+  MockModule module;
+  EXPECT_CALL(module, TimeUntilNextProcess()).WillRepeatedly(Return(0));
+  EXPECT_CALL(module, Process())
+      .WillOnce(DoAll(SetEvent(event.get()),
+                      Increment(&process_count),
+                      Return(0)))
+      .WillRepeatedly(DoAll(Increment(&process_count), Return(0)));
+
+  ASSERT_EQ(0, thread.RegisterModule(&module));
+  ASSERT_EQ(0, thread.Start());
+
+  EXPECT_EQ(kEventSignaled, event->Wait(100));
+  ASSERT_EQ(0, thread.DeRegisterModule(&module));
+  EXPECT_GE(process_count, 1);
+  int count_after_deregister = process_count;
+
+  // We shouldn't get any more callbacks.
+  EXPECT_EQ(kEventTimeout, event->Wait(20));
+  EXPECT_EQ(count_after_deregister, process_count);
+  EXPECT_EQ(0, thread.Stop());
+}
+
+// Helper function for testing receiving a callback after a certain amount of
+// time.  There's some variance of timing built into it to reduce chance of
+// flakiness on bots.
+void ProcessCallAfterAFewMs(int64_t milliseconds) {
+  ProcessThreadImpl thread;
+  ASSERT_EQ(0, thread.Start());
+
+  rtc::scoped_ptr<EventWrapper> event(EventWrapper::Create());
+
+  MockModule module;
+  int64_t start_time = 0;
+  int64_t called_time = 0;
+  EXPECT_CALL(module, TimeUntilNextProcess())
+      .WillOnce(DoAll(SetTimestamp(&start_time),
+                      Return(milliseconds)))
+      .WillRepeatedly(Return(milliseconds));
+  EXPECT_CALL(module, Process())
+      .WillOnce(DoAll(SetTimestamp(&called_time),
+                      SetEvent(event.get()),
+                      Return(0)));
+
+  EXPECT_EQ(0, thread.RegisterModule(&module));
+
+  // Add a buffer of 50ms due to slowness of some trybots
+  // (e.g. win_drmemory_light)
+  EXPECT_EQ(kEventSignaled, event->Wait(milliseconds + 50));
+  ASSERT_EQ(0, thread.Stop());
+
+  ASSERT_GT(start_time, 0);
+  ASSERT_GT(called_time, 0);
+  // Use >= instead of > since due to rounding and timer accuracy (or lack
+  // thereof), can make the test run in "0"ms time.
+  EXPECT_GE(called_time, start_time);
+  // Check for an acceptable range.
+  uint32 diff = called_time - start_time;
+  EXPECT_GE(diff, milliseconds - 15);
+  EXPECT_LT(diff, milliseconds + 15);
+}
+
+TEST(ProcessThreadImpl, ProcessCallAfter5ms) {
+  ProcessCallAfterAFewMs(5);
+}
+
+TEST(ProcessThreadImpl, ProcessCallAfter50ms) {
+  ProcessCallAfterAFewMs(50);
+}
+
+TEST(ProcessThreadImpl, ProcessCallAfter200ms) {
+  ProcessCallAfterAFewMs(200);
+}
+
+// Runs callbacks with the goal of getting up to 50 callbacks within a second
+// (on average 1 callback every 20ms).  On real hardware, we're usually pretty
+// close to that, but the test bots that run on virtual machines, will
+// typically be in the range 30-40 callbacks.
+TEST(ProcessThreadImpl, MANUAL_Process50Times) {
+  ProcessThreadImpl thread;
+  ASSERT_EQ(0, thread.Start());
+
+  rtc::scoped_ptr<EventWrapper> event(EventWrapper::Create());
+
+  MockModule module;
+  int callback_count = 0;
+  // Ask for a callback after 20ms.
+  EXPECT_CALL(module, TimeUntilNextProcess())
+      .WillRepeatedly(Return(20));
+  EXPECT_CALL(module, Process())
+      .WillRepeatedly(DoAll(Increment(&callback_count),
+                            Return(0)));
+
+  EXPECT_EQ(0, thread.RegisterModule(&module));
+
+  EXPECT_EQ(kEventTimeout, event->Wait(1000));
+  ASSERT_EQ(0, thread.Stop());
+
+  printf("Callback count: %i\n", callback_count);
+  // Check that we got called back up to 50 times.
+  // Some of the try bots run on slow virtual machines, so the lower bound
+  // is much more relaxed to avoid flakiness.
+  EXPECT_GE(callback_count, 25);
+  EXPECT_LE(callback_count, 50);
+}
+
+// Tests that we can wake up the worker thread to give us a callback right
+// away when we know the thread is sleeping.
+TEST(ProcessThreadImpl, WakeUp) {
+  ProcessThreadImpl thread;
+  ASSERT_EQ(0, thread.Start());
+
+  rtc::scoped_ptr<EventWrapper> started(EventWrapper::Create());
+  rtc::scoped_ptr<EventWrapper> called(EventWrapper::Create());
+
+  MockModule module;
+  int64_t start_time = 0;
+  int64_t called_time = 0;
+  // Ask for a callback after 1000ms first, then 0ms.
+  EXPECT_CALL(module, TimeUntilNextProcess())
+      .WillOnce(DoAll(SetTimestamp(&start_time),
+                      SetEvent(started.get()),
+                      Return(1000)))
+      .WillRepeatedly(Return(0));
+  EXPECT_CALL(module, Process())
+      .WillOnce(DoAll(SetTimestamp(&called_time),
+                      SetEvent(called.get()),
+                      Return(0)))
+      .WillRepeatedly(Return(0));
+
+  EXPECT_EQ(0, thread.RegisterModule(&module));
+
+  EXPECT_EQ(kEventSignaled, started->Wait(100));
+  thread.WakeUp(&module);
+  EXPECT_EQ(kEventSignaled, called->Wait(100));
+  ASSERT_EQ(0, thread.Stop());
+
+  ASSERT_GT(start_time, 0);
+  ASSERT_GT(called_time, 0);
+  EXPECT_GE(called_time, start_time);
+  uint32 diff = called_time - start_time;
+  // We should have been called back much quicker than 1sec.
+  EXPECT_LE(diff, 100u);
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/video_capture/test/video_capture_unittest.cc b/webrtc/modules/video_capture/test/video_capture_unittest.cc
index 8635c9c44..2909fe2d6 100644
--- a/webrtc/modules/video_capture/test/video_capture_unittest.cc
+++ b/webrtc/modules/video_capture/test/video_capture_unittest.cc
@@ -436,7 +436,7 @@ class VideoCaptureExternalTest : public testing::Test {
  public:
   void SetUp() {
     capture_module_ = VideoCaptureFactory::Create(0, capture_input_interface_);
-    process_module_ = webrtc::ProcessThread::CreateProcessThread();
+    process_module_ = webrtc::ProcessThread::Create();
     process_module_->Start();
     process_module_->RegisterModule(capture_module_);
 
@@ -464,12 +464,11 @@ class VideoCaptureExternalTest : public testing::Test {
 
   void TearDown() {
     process_module_->Stop();
-    webrtc::ProcessThread::DestroyProcessThread(process_module_);
   }
 
   webrtc::VideoCaptureExternal* capture_input_interface_;
   webrtc::scoped_refptr<VideoCaptureModule> capture_module_;
-  webrtc::ProcessThread* process_module_;
+  rtc::scoped_ptr<webrtc::ProcessThread> process_module_;
   webrtc::I420VideoFrame test_frame_;
   TestVideoCaptureCallback capture_callback_;
   TestVideoCaptureFeedBack capture_feedback_;
diff --git a/webrtc/video_engine/vie_shared_data.cc b/webrtc/video_engine/vie_shared_data.cc
index 11f136ba5..bfb579b09 100644
--- a/webrtc/video_engine/vie_shared_data.cc
+++ b/webrtc/video_engine/vie_shared_data.cc
@@ -24,11 +24,11 @@ ViESharedData::ViESharedData(const Config& config)
       channel_manager_(new ViEChannelManager(0, number_cores_, config)),
       input_manager_(new ViEInputManager(0, config)),
       render_manager_(new ViERenderManager(0)),
-      module_process_thread_(ProcessThread::CreateProcessThread()),
+      module_process_thread_(ProcessThread::Create()),
       last_error_(0) {
   Trace::CreateTrace();
-  channel_manager_->SetModuleProcessThread(module_process_thread_);
-  input_manager_->SetModuleProcessThread(module_process_thread_);
+  channel_manager_->SetModuleProcessThread(module_process_thread_.get());
+  input_manager_->SetModuleProcessThread(module_process_thread_.get());
   module_process_thread_->Start();
 }
 
@@ -39,7 +39,6 @@ ViESharedData::~ViESharedData() {
   render_manager_.reset();
 
   module_process_thread_->Stop();
-  ProcessThread::DestroyProcessThread(module_process_thread_);
   Trace::ReturnTrace();
 }
 
diff --git a/webrtc/video_engine/vie_shared_data.h b/webrtc/video_engine/vie_shared_data.h
index 0d8d100af..43b41d04f 100644
--- a/webrtc/video_engine/vie_shared_data.h
+++ b/webrtc/video_engine/vie_shared_data.h
@@ -16,7 +16,7 @@
 
 #include <map>
 
-#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+#include "webrtc/base/scoped_ptr.h"
 
 namespace webrtc {
 
@@ -48,10 +48,10 @@ class ViESharedData {
  private:
   const int number_cores_;
 
-  scoped_ptr<ViEChannelManager> channel_manager_;
-  scoped_ptr<ViEInputManager> input_manager_;
-  scoped_ptr<ViERenderManager> render_manager_;
-  ProcessThread* module_process_thread_;
+  rtc::scoped_ptr<ViEChannelManager> channel_manager_;
+  rtc::scoped_ptr<ViEInputManager> input_manager_;
+  rtc::scoped_ptr<ViERenderManager> render_manager_;
+  rtc::scoped_ptr<ProcessThread> module_process_thread_;
   mutable int last_error_;
 
   std::map<int, CpuOveruseObserver*> overuse_observers_;
diff --git a/webrtc/voice_engine/shared_data.cc b/webrtc/voice_engine/shared_data.cc
index 218784474..ad00e038f 100644
--- a/webrtc/voice_engine/shared_data.cc
+++ b/webrtc/voice_engine/shared_data.cc
@@ -29,7 +29,7 @@ SharedData::SharedData(const Config& config) :
     _channelManager(_gInstanceCounter, config),
     _engineStatistics(_gInstanceCounter),
     _audioDevicePtr(NULL),
-    _moduleProcessThreadPtr(ProcessThread::CreateProcessThread()),
+    _moduleProcessThreadPtr(ProcessThread::Create()),
     _externalRecording(false),
     _externalPlayout(false)
 {
@@ -55,7 +55,7 @@ SharedData::~SharedData()
         _audioDevicePtr->Release();
     }
     delete _apiCritPtr;
-    ProcessThread::DestroyProcessThread(_moduleProcessThreadPtr);
+    _moduleProcessThreadPtr->Stop();
     Trace::ReturnTrace();
 }
 
diff --git a/webrtc/voice_engine/shared_data.h b/webrtc/voice_engine/shared_data.h
index dd76e96ab..3ab1d45ac 100644
--- a/webrtc/voice_engine/shared_data.h
+++ b/webrtc/voice_engine/shared_data.h
@@ -11,10 +11,10 @@
 #ifndef WEBRTC_VOICE_ENGINE_SHARED_DATA_H
 #define WEBRTC_VOICE_ENGINE_SHARED_DATA_H
 
+#include "webrtc/base/scoped_ptr.h"
 #include "webrtc/modules/audio_device/include/audio_device.h"
 #include "webrtc/modules/audio_processing/include/audio_processing.h"
 #include "webrtc/modules/utility/interface/process_thread.h"
-#include "webrtc/system_wrappers/interface/scoped_ptr.h"
 #include "webrtc/voice_engine/channel_manager.h"
 #include "webrtc/voice_engine/statistics.h"
 #include "webrtc/voice_engine/voice_engine_defines.h"
@@ -48,7 +48,7 @@ public:
     void set_ext_recording(bool value) { _externalRecording = value; }
     bool ext_playout() const { return _externalPlayout; }
     void set_ext_playout(bool value) { _externalPlayout = value; }
-    ProcessThread* process_thread() { return _moduleProcessThreadPtr; }
+    ProcessThread* process_thread() { return _moduleProcessThreadPtr.get(); }
     AudioDeviceModule::AudioLayer audio_device_layer() const {
       return _audioDeviceLayer;
     }
@@ -73,8 +73,8 @@ protected:
     AudioDeviceModule* _audioDevicePtr;
     OutputMixer* _outputMixerPtr;
     TransmitMixer* _transmitMixerPtr;
-    scoped_ptr<AudioProcessing> audioproc_;
-    ProcessThread* _moduleProcessThreadPtr;
+    rtc::scoped_ptr<AudioProcessing> audioproc_;
+    rtc::scoped_ptr<ProcessThread> _moduleProcessThreadPtr;
 
     bool _externalRecording;
     bool _externalPlayout;