Revert 206507 "Move message_pump to base/message_loop."

trunk/src/base/message_loop/message_pump_win.cc

Index: trunk/src/base/message_loop/message_pump_win.cc
===================================================================
--- trunk/src/base/message_loop/message_pump_win.cc	(revision 206508)
+++ trunk/src/base/message_loop/message_pump_win.cc	(working copy)
@@ -1,686 +0,0 @@
-// 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/message_loop/message_pump_win.h"
-
-#include <math.h>
-
-#include "base/debug/trace_event.h"
-#include "base/message_loop/message_loop.h"
-#include "base/metrics/histogram.h"
-#include "base/process_util.h"
-#include "base/stringprintf.h"
-#include "base/win/wrapped_window_proc.h"
-
-namespace base {
-
-namespace {
-
-enum MessageLoopProblems {
-  MESSAGE_POST_ERROR,
-  COMPLETION_POST_ERROR,
-  SET_TIMER_ERROR,
-  MESSAGE_LOOP_PROBLEM_MAX,
-};
-
-}  // namespace
-
-static const wchar_t kWndClassFormat[] = L"Chrome_MessagePumpWindow_%p";
-
-// Message sent to get an additional time slice for pumping (processing) another
-// task (a series of such messages creates a continuous task pump).
-static const int kMsgHaveWork = WM_USER + 1;
-
-//-----------------------------------------------------------------------------
-// MessagePumpWin public:
-
-void MessagePumpWin::AddObserver(MessagePumpObserver* observer) {
-  observers_.AddObserver(observer);
-}
-
-void MessagePumpWin::RemoveObserver(MessagePumpObserver* observer) {
-  observers_.RemoveObserver(observer);
-}
-
-void MessagePumpWin::WillProcessMessage(const MSG& msg) {
-  FOR_EACH_OBSERVER(MessagePumpObserver, observers_, WillProcessEvent(msg));
-}
-
-void MessagePumpWin::DidProcessMessage(const MSG& msg) {
-  FOR_EACH_OBSERVER(MessagePumpObserver, observers_, DidProcessEvent(msg));
-}
-
-void MessagePumpWin::RunWithDispatcher(
-    Delegate* delegate, MessagePumpDispatcher* dispatcher) {
-  RunState s;
-  s.delegate = delegate;
-  s.dispatcher = dispatcher;
-  s.should_quit = false;
-  s.run_depth = state_ ? state_->run_depth + 1 : 1;
-
-  RunState* previous_state = state_;
-  state_ = &s;
-
-  DoRunLoop();
-
-  state_ = previous_state;
-}
-
-void MessagePumpWin::Quit() {
-  DCHECK(state_);
-  state_->should_quit = true;
-}
-
-//-----------------------------------------------------------------------------
-// MessagePumpWin protected:
-
-int MessagePumpWin::GetCurrentDelay() const {
-  if (delayed_work_time_.is_null())
-    return -1;
-
-  // Be careful here.  TimeDelta has a precision of microseconds, but we want a
-  // value in milliseconds.  If there are 5.5ms left, should the delay be 5 or
-  // 6?  It should be 6 to avoid executing delayed work too early.
-  double timeout =
-      ceil((delayed_work_time_ - TimeTicks::Now()).InMillisecondsF());
-
-  // If this value is negative, then we need to run delayed work soon.
-  int delay = static_cast<int>(timeout);
-  if (delay < 0)
-    delay = 0;
-
-  return delay;
-}
-
-//-----------------------------------------------------------------------------
-// MessagePumpForUI public:
-
-MessagePumpForUI::MessagePumpForUI()
-    : atom_(0),
-      message_filter_(new MessageFilter) {
-  InitMessageWnd();
-}
-
-MessagePumpForUI::~MessagePumpForUI() {
-  DestroyWindow(message_hwnd_);
-  UnregisterClass(MAKEINTATOM(atom_),
-                  GetModuleFromAddress(&WndProcThunk));
-}
-
-void MessagePumpForUI::ScheduleWork() {
-  if (InterlockedExchange(&have_work_, 1))
-    return;  // Someone else continued the pumping.
-
-  // Make sure the MessagePump does some work for us.
-  BOOL ret = PostMessage(message_hwnd_, kMsgHaveWork,
-                         reinterpret_cast<WPARAM>(this), 0);
-  if (ret)
-    return;  // There was room in the Window Message queue.
-
-  // We have failed to insert a have-work message, so there is a chance that we
-  // will starve tasks/timers while sitting in a nested message loop.  Nested
-  // loops only look at Windows Message queues, and don't look at *our* task
-  // queues, etc., so we might not get a time slice in such. :-(
-  // We could abort here, but the fear is that this failure mode is plausibly
-  // common (queue is full, of about 2000 messages), so we'll do a near-graceful
-  // recovery.  Nested loops are pretty transient (we think), so this will
-  // probably be recoverable.
-  InterlockedExchange(&have_work_, 0);  // Clarify that we didn't really insert.
-  UMA_HISTOGRAM_ENUMERATION("Chrome.MessageLoopProblem", MESSAGE_POST_ERROR,
-                            MESSAGE_LOOP_PROBLEM_MAX);
-}
-
-void MessagePumpForUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time) {
-  //
-  // We would *like* to provide high resolution timers.  Windows timers using
-  // SetTimer() have a 10ms granularity.  We have to use WM_TIMER as a wakeup
-  // mechanism because the application can enter modal windows loops where it
-  // is not running our MessageLoop; the only way to have our timers fire in
-  // these cases is to post messages there.
-  //
-  // To provide sub-10ms timers, we process timers directly from our run loop.
-  // For the common case, timers will be processed there as the run loop does
-  // its normal work.  However, we *also* set the system timer so that WM_TIMER
-  // events fire.  This mops up the case of timers not being able to work in
-  // modal message loops.  It is possible for the SetTimer to pop and have no
-  // pending timers, because they could have already been processed by the
-  // run loop itself.
-  //
-  // We use a single SetTimer corresponding to the timer that will expire
-  // soonest.  As new timers are created and destroyed, we update SetTimer.
-  // Getting a spurrious SetTimer event firing is benign, as we'll just be
-  // processing an empty timer queue.
-  //
-  delayed_work_time_ = delayed_work_time;
-
-  int delay_msec = GetCurrentDelay();
-  DCHECK_GE(delay_msec, 0);
-  if (delay_msec < USER_TIMER_MINIMUM)
-    delay_msec = USER_TIMER_MINIMUM;
-
-  // Create a WM_TIMER event that will wake us up to check for any pending
-  // timers (in case we are running within a nested, external sub-pump).
-  BOOL ret = SetTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this),
-                      delay_msec, NULL);
-  if (ret)
-    return;
-  // If we can't set timers, we are in big trouble... but cross our fingers for
-  // now.
-  // TODO(jar): If we don't see this error, use a CHECK() here instead.
-  UMA_HISTOGRAM_ENUMERATION("Chrome.MessageLoopProblem", SET_TIMER_ERROR,
-                            MESSAGE_LOOP_PROBLEM_MAX);
-}
-
-void MessagePumpForUI::PumpOutPendingPaintMessages() {
-  // If we are being called outside of the context of Run, then don't try to do
-  // any work.
-  if (!state_)
-    return;
-
-  // Create a mini-message-pump to force immediate processing of only Windows
-  // WM_PAINT messages.  Don't provide an infinite loop, but do enough peeking
-  // to get the job done.  Actual common max is 4 peeks, but we'll be a little
-  // safe here.
-  const int kMaxPeekCount = 20;
-  int peek_count;
-  for (peek_count = 0; peek_count < kMaxPeekCount; ++peek_count) {
-    MSG msg;
-    if (!PeekMessage(&msg, NULL, 0, 0, PM_REMOVE | PM_QS_PAINT))
-      break;
-    ProcessMessageHelper(msg);
-    if (state_->should_quit)  // Handle WM_QUIT.
-      break;
-  }
-  // Histogram what was really being used, to help to adjust kMaxPeekCount.
-  DHISTOGRAM_COUNTS("Loop.PumpOutPendingPaintMessages Peeks", peek_count);
-}
-
-//-----------------------------------------------------------------------------
-// MessagePumpForUI private:
-
-// static
-LRESULT CALLBACK MessagePumpForUI::WndProcThunk(
-    HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
-  switch (message) {
-    case kMsgHaveWork:
-      reinterpret_cast<MessagePumpForUI*>(wparam)->HandleWorkMessage();
-      break;
-    case WM_TIMER:
-      reinterpret_cast<MessagePumpForUI*>(wparam)->HandleTimerMessage();
-      break;
-  }
-  return DefWindowProc(hwnd, message, wparam, lparam);
-}
-
-void MessagePumpForUI::DoRunLoop() {
-  // IF this was just a simple PeekMessage() loop (servicing all possible work
-  // queues), then Windows would try to achieve the following order according
-  // to MSDN documentation about PeekMessage with no filter):
-  //    * Sent messages
-  //    * Posted messages
-  //    * Sent messages (again)
-  //    * WM_PAINT messages
-  //    * WM_TIMER messages
-  //
-  // Summary: none of the above classes is starved, and sent messages has twice
-  // the chance of being processed (i.e., reduced service time).
-
-  for (;;) {
-    // If we do any work, we may create more messages etc., and more work may
-    // possibly be waiting in another task group.  When we (for example)
-    // ProcessNextWindowsMessage(), there is a good chance there are still more
-    // messages waiting.  On the other hand, when any of these methods return
-    // having done no work, then it is pretty unlikely that calling them again
-    // quickly will find any work to do.  Finally, if they all say they had no
-    // work, then it is a good time to consider sleeping (waiting) for more
-    // work.
-
-    bool more_work_is_plausible = ProcessNextWindowsMessage();
-    if (state_->should_quit)
-      break;
-
-    more_work_is_plausible |= state_->delegate->DoWork();
-    if (state_->should_quit)
-      break;
-
-    more_work_is_plausible |=
-        state_->delegate->DoDelayedWork(&delayed_work_time_);
-    // If we did not process any delayed work, then we can assume that our
-    // existing WM_TIMER if any will fire when delayed work should run.  We
-    // don't want to disturb that timer if it is already in flight.  However,
-    // if we did do all remaining delayed work, then lets kill the WM_TIMER.
-    if (more_work_is_plausible && delayed_work_time_.is_null())
-      KillTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this));
-    if (state_->should_quit)
-      break;
-
-    if (more_work_is_plausible)
-      continue;
-
-    more_work_is_plausible = state_->delegate->DoIdleWork();
-    if (state_->should_quit)
-      break;
-
-    if (more_work_is_plausible)
-      continue;
-
-    WaitForWork();  // Wait (sleep) until we have work to do again.
-  }
-}
-
-void MessagePumpForUI::InitMessageWnd() {
-  // Generate a unique window class name.
-  string16 class_name = StringPrintf(kWndClassFormat, this);
-
-  HINSTANCE instance = GetModuleFromAddress(&WndProcThunk);
-  WNDCLASSEX wc = {0};
-  wc.cbSize = sizeof(wc);
-  wc.lpfnWndProc = base::win::WrappedWindowProc<WndProcThunk>;
-  wc.hInstance = instance;
-  wc.lpszClassName = class_name.c_str();
-  atom_ = RegisterClassEx(&wc);
-  DCHECK(atom_);
-
-  message_hwnd_ = CreateWindow(MAKEINTATOM(atom_), 0, 0, 0, 0, 0, 0,
-                               HWND_MESSAGE, 0, instance, 0);
-  DCHECK(message_hwnd_);
-}
-
-void MessagePumpForUI::WaitForWork() {
-  // Wait until a message is available, up to the time needed by the timer
-  // manager to fire the next set of timers.
-  int delay = GetCurrentDelay();
-  if (delay < 0)  // Negative value means no timers waiting.
-    delay = INFINITE;
-
-  DWORD result;
-  result = MsgWaitForMultipleObjectsEx(0, NULL, delay, QS_ALLINPUT,
-                                       MWMO_INPUTAVAILABLE);
-
-  if (WAIT_OBJECT_0 == result) {
-    // A WM_* message is available.
-    // If a parent child relationship exists between windows across threads
-    // then their thread inputs are implicitly attached.
-    // This causes the MsgWaitForMultipleObjectsEx API to return indicating
-    // that messages are ready for processing (Specifically, mouse messages
-    // intended for the child window may appear if the child window has
-    // capture).
-    // The subsequent PeekMessages call may fail to return any messages thus
-    // causing us to enter a tight loop at times.
-    // The WaitMessage call below is a workaround to give the child window
-    // some time to process its input messages.
-    MSG msg = {0};
-    DWORD queue_status = GetQueueStatus(QS_MOUSE);
-    if (HIWORD(queue_status) & QS_MOUSE &&
-        !PeekMessage(&msg, NULL, WM_MOUSEFIRST, WM_MOUSELAST, PM_NOREMOVE)) {
-      WaitMessage();
-    }
-    return;
-  }
-
-  DCHECK_NE(WAIT_FAILED, result) << GetLastError();
-}
-
-void MessagePumpForUI::HandleWorkMessage() {
-  // If we are being called outside of the context of Run, then don't try to do
-  // any work.  This could correspond to a MessageBox call or something of that
-  // sort.
-  if (!state_) {
-    // Since we handled a kMsgHaveWork message, we must still update this flag.
-    InterlockedExchange(&have_work_, 0);
-    return;
-  }
-
-  // Let whatever would have run had we not been putting messages in the queue
-  // run now.  This is an attempt to make our dummy message not starve other
-  // messages that may be in the Windows message queue.
-  ProcessPumpReplacementMessage();
-
-  // Now give the delegate a chance to do some work.  He'll let us know if he
-  // needs to do more work.
-  if (state_->delegate->DoWork())
-    ScheduleWork();
-}
-
-void MessagePumpForUI::HandleTimerMessage() {
-  KillTimer(message_hwnd_, reinterpret_cast<UINT_PTR>(this));
-
-  // If we are being called outside of the context of Run, then don't do
-  // anything.  This could correspond to a MessageBox call or something of
-  // that sort.
-  if (!state_)
-    return;
-
-  state_->delegate->DoDelayedWork(&delayed_work_time_);
-  if (!delayed_work_time_.is_null()) {
-    // A bit gratuitous to set delayed_work_time_ again, but oh well.
-    ScheduleDelayedWork(delayed_work_time_);
-  }
-}
-
-bool MessagePumpForUI::ProcessNextWindowsMessage() {
-  // If there are sent messages in the queue then PeekMessage internally
-  // dispatches the message and returns false. We return true in this
-  // case to ensure that the message loop peeks again instead of calling
-  // MsgWaitForMultipleObjectsEx again.
-  bool sent_messages_in_queue = false;
-  DWORD queue_status = GetQueueStatus(QS_SENDMESSAGE);
-  if (HIWORD(queue_status) & QS_SENDMESSAGE)
-    sent_messages_in_queue = true;
-
-  MSG msg;
-  if (message_filter_->DoPeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
-    return ProcessMessageHelper(msg);
-
-  return sent_messages_in_queue;
-}
-
-bool MessagePumpForUI::ProcessMessageHelper(const MSG& msg) {
-  TRACE_EVENT1("base", "MessagePumpForUI::ProcessMessageHelper",
-               "message", msg.message);
-  if (WM_QUIT == msg.message) {
-    // Repost the QUIT message so that it will be retrieved by the primary
-    // GetMessage() loop.
-    state_->should_quit = true;
-    PostQuitMessage(static_cast<int>(msg.wParam));
-    return false;
-  }
-
-  // While running our main message pump, we discard kMsgHaveWork messages.
-  if (msg.message == kMsgHaveWork && msg.hwnd == message_hwnd_)
-    return ProcessPumpReplacementMessage();
-
-  if (CallMsgFilter(const_cast<MSG*>(&msg), kMessageFilterCode))
-    return true;
-
-  WillProcessMessage(msg);
-
-  if (!message_filter_->ProcessMessage(msg)) {
-    if (state_->dispatcher) {
-      if (!state_->dispatcher->Dispatch(msg))
-        state_->should_quit = true;
-    } else {
-      TranslateMessage(&msg);
-      DispatchMessage(&msg);
-    }
-  }
-
-  DidProcessMessage(msg);
-  return true;
-}
-
-bool MessagePumpForUI::ProcessPumpReplacementMessage() {
-  // When we encounter a kMsgHaveWork message, this method is called to peek
-  // and process a replacement message, such as a WM_PAINT or WM_TIMER.  The
-  // goal is to make the kMsgHaveWork as non-intrusive as possible, even though
-  // a continuous stream of such messages are posted.  This method carefully
-  // peeks a message while there is no chance for a kMsgHaveWork to be pending,
-  // then resets the have_work_ flag (allowing a replacement kMsgHaveWork to
-  // possibly be posted), and finally dispatches that peeked replacement.  Note
-  // that the re-post of kMsgHaveWork may be asynchronous to this thread!!
-
-  bool have_message = false;
-  MSG msg;
-  // We should not process all window messages if we are in the context of an
-  // OS modal loop, i.e. in the context of a windows API call like MessageBox.
-  // This is to ensure that these messages are peeked out by the OS modal loop.
-  if (MessageLoop::current()->os_modal_loop()) {
-    // We only peek out WM_PAINT and WM_TIMER here for reasons mentioned above.
-    have_message = PeekMessage(&msg, NULL, WM_PAINT, WM_PAINT, PM_REMOVE) ||
-                   PeekMessage(&msg, NULL, WM_TIMER, WM_TIMER, PM_REMOVE);
-  } else {
-    have_message = !!message_filter_->DoPeekMessage(&msg, NULL, 0, 0,
-                                                    PM_REMOVE);
-  }
-
-  DCHECK(!have_message || kMsgHaveWork != msg.message ||
-         msg.hwnd != message_hwnd_);
-
-  // Since we discarded a kMsgHaveWork message, we must update the flag.
-  int old_have_work = InterlockedExchange(&have_work_, 0);
-  DCHECK(old_have_work);
-
-  // We don't need a special time slice if we didn't have_message to process.
-  if (!have_message)
-    return false;
-
-  // Guarantee we'll get another time slice in the case where we go into native
-  // windows code.   This ScheduleWork() may hurt performance a tiny bit when
-  // tasks appear very infrequently, but when the event queue is busy, the
-  // kMsgHaveWork events get (percentage wise) rarer and rarer.
-  ScheduleWork();
-  return ProcessMessageHelper(msg);
-}
-
-void MessagePumpForUI::SetMessageFilter(
-    scoped_ptr<MessageFilter> message_filter) {
-  message_filter_ = message_filter.Pass();
-}
-
-//-----------------------------------------------------------------------------
-// MessagePumpForIO public:
-
-MessagePumpForIO::MessagePumpForIO() {
-  port_.Set(CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, NULL, 1));
-  DCHECK(port_.IsValid());
-}
-
-void MessagePumpForIO::ScheduleWork() {
-  if (InterlockedExchange(&have_work_, 1))
-    return;  // Someone else continued the pumping.
-
-  // Make sure the MessagePump does some work for us.
-  BOOL ret = PostQueuedCompletionStatus(port_, 0,
-                                        reinterpret_cast<ULONG_PTR>(this),
-                                        reinterpret_cast<OVERLAPPED*>(this));
-  if (ret)
-    return;  // Post worked perfectly.
-
-  // See comment in MessagePumpForUI::ScheduleWork() for this error recovery.
-  InterlockedExchange(&have_work_, 0);  // Clarify that we didn't succeed.
-  UMA_HISTOGRAM_ENUMERATION("Chrome.MessageLoopProblem", COMPLETION_POST_ERROR,
-                            MESSAGE_LOOP_PROBLEM_MAX);
-}
-
-void MessagePumpForIO::ScheduleDelayedWork(const TimeTicks& delayed_work_time) {
-  // We know that we can't be blocked right now since this method can only be
-  // called on the same thread as Run, so we only need to update our record of
-  // how long to sleep when we do sleep.
-  delayed_work_time_ = delayed_work_time;
-}
-
-void MessagePumpForIO::RegisterIOHandler(HANDLE file_handle,
-                                         IOHandler* handler) {
-  ULONG_PTR key = HandlerToKey(handler, true);
-  HANDLE port = CreateIoCompletionPort(file_handle, port_, key, 1);
-  DPCHECK(port);
-}
-
-bool MessagePumpForIO::RegisterJobObject(HANDLE job_handle,
-                                         IOHandler* handler) {
-  // Job object notifications use the OVERLAPPED pointer to carry the message
-  // data. Mark the completion key correspondingly, so we will not try to
-  // convert OVERLAPPED* to IOContext*.
-  ULONG_PTR key = HandlerToKey(handler, false);
-  JOBOBJECT_ASSOCIATE_COMPLETION_PORT info;
-  info.CompletionKey = reinterpret_cast<void*>(key);
-  info.CompletionPort = port_;
-  return SetInformationJobObject(job_handle,
-                                 JobObjectAssociateCompletionPortInformation,
-                                 &info,
-                                 sizeof(info)) != FALSE;
-}
-
-//-----------------------------------------------------------------------------
-// MessagePumpForIO private:
-
-void MessagePumpForIO::DoRunLoop() {
-  for (;;) {
-    // If we do any work, we may create more messages etc., and more work may
-    // possibly be waiting in another task group.  When we (for example)
-    // WaitForIOCompletion(), there is a good chance there are still more
-    // messages waiting.  On the other hand, when any of these methods return
-    // having done no work, then it is pretty unlikely that calling them
-    // again quickly will find any work to do.  Finally, if they all say they
-    // had no work, then it is a good time to consider sleeping (waiting) for
-    // more work.
-
-    bool more_work_is_plausible = state_->delegate->DoWork();
-    if (state_->should_quit)
-      break;
-
-    more_work_is_plausible |= WaitForIOCompletion(0, NULL);
-    if (state_->should_quit)
-      break;
-
-    more_work_is_plausible |=
-        state_->delegate->DoDelayedWork(&delayed_work_time_);
-    if (state_->should_quit)
-      break;
-
-    if (more_work_is_plausible)
-      continue;
-
-    more_work_is_plausible = state_->delegate->DoIdleWork();
-    if (state_->should_quit)
-      break;
-
-    if (more_work_is_plausible)
-      continue;
-
-    WaitForWork();  // Wait (sleep) until we have work to do again.
-  }
-}
-
-// Wait until IO completes, up to the time needed by the timer manager to fire
-// the next set of timers.
-void MessagePumpForIO::WaitForWork() {
-  // We do not support nested IO message loops. This is to avoid messy
-  // recursion problems.
-  DCHECK_EQ(1, state_->run_depth) << "Cannot nest an IO message loop!";
-
-  int timeout = GetCurrentDelay();
-  if (timeout < 0)  // Negative value means no timers waiting.
-    timeout = INFINITE;
-
-  WaitForIOCompletion(timeout, NULL);
-}
-
-bool MessagePumpForIO::WaitForIOCompletion(DWORD timeout, IOHandler* filter) {
-  IOItem item;
-  if (completed_io_.empty() || !MatchCompletedIOItem(filter, &item)) {
-    // We have to ask the system for another IO completion.
-    if (!GetIOItem(timeout, &item))
-      return false;
-
-    if (ProcessInternalIOItem(item))
-      return true;
-  }
-
-  // If |item.has_valid_io_context| is false then |item.context| does not point
-  // to a context structure, and so should not be dereferenced, although it may
-  // still hold valid non-pointer data.
-  if (!item.has_valid_io_context || item.context->handler) {
-    if (filter && item.handler != filter) {
-      // Save this item for later
-      completed_io_.push_back(item);
-    } else {
-      DCHECK(!item.has_valid_io_context ||
-             (item.context->handler == item.handler));
-      WillProcessIOEvent();
-      item.handler->OnIOCompleted(item.context, item.bytes_transfered,
-                                  item.error);
-      DidProcessIOEvent();
-    }
-  } else {
-    // The handler must be gone by now, just cleanup the mess.
-    delete item.context;
-  }
-  return true;
-}
-
-// Asks the OS for another IO completion result.
-bool MessagePumpForIO::GetIOItem(DWORD timeout, IOItem* item) {
-  memset(item, 0, sizeof(*item));
-  ULONG_PTR key = NULL;
-  OVERLAPPED* overlapped = NULL;
-  if (!GetQueuedCompletionStatus(port_.Get(), &item->bytes_transfered, &key,
-                                 &overlapped, timeout)) {
-    if (!overlapped)
-      return false;  // Nothing in the queue.
-    item->error = GetLastError();
-    item->bytes_transfered = 0;
-  }
-
-  item->handler = KeyToHandler(key, &item->has_valid_io_context);
-  item->context = reinterpret_cast<IOContext*>(overlapped);
-  return true;
-}
-
-bool MessagePumpForIO::ProcessInternalIOItem(const IOItem& item) {
-  if (this == reinterpret_cast<MessagePumpForIO*>(item.context) &&
-      this == reinterpret_cast<MessagePumpForIO*>(item.handler)) {
-    // This is our internal completion.
-    DCHECK(!item.bytes_transfered);
-    InterlockedExchange(&have_work_, 0);
-    return true;
-  }
-  return false;
-}
-
-// Returns a completion item that was previously received.
-bool MessagePumpForIO::MatchCompletedIOItem(IOHandler* filter, IOItem* item) {
-  DCHECK(!completed_io_.empty());
-  for (std::list<IOItem>::iterator it = completed_io_.begin();
-       it != completed_io_.end(); ++it) {
-    if (!filter || it->handler == filter) {
-      *item = *it;
-      completed_io_.erase(it);
-      return true;
-    }
-  }
-  return false;
-}
-
-void MessagePumpForIO::AddIOObserver(IOObserver *obs) {
-  io_observers_.AddObserver(obs);
-}
-
-void MessagePumpForIO::RemoveIOObserver(IOObserver *obs) {
-  io_observers_.RemoveObserver(obs);
-}
-
-void MessagePumpForIO::WillProcessIOEvent() {
-  FOR_EACH_OBSERVER(IOObserver, io_observers_, WillProcessIOEvent());
-}
-
-void MessagePumpForIO::DidProcessIOEvent() {
-  FOR_EACH_OBSERVER(IOObserver, io_observers_, DidProcessIOEvent());
-}
-
-// static
-ULONG_PTR MessagePumpForIO::HandlerToKey(IOHandler* handler,
-                                         bool has_valid_io_context) {
-  ULONG_PTR key = reinterpret_cast<ULONG_PTR>(handler);
-
-  // |IOHandler| is at least pointer-size aligned, so the lowest two bits are
-  // always cleared. We use the lowest bit to distinguish completion keys with
-  // and without the associated |IOContext|.
-  DCHECK((key & 1) == 0);
-
-  // Mark the completion key as context-less.
-  if (!has_valid_io_context)
-    key = key | 1;
-  return key;
-}
-
-// static
-MessagePumpForIO::IOHandler* MessagePumpForIO::KeyToHandler(
-    ULONG_PTR key,
-    bool* has_valid_io_context) {
-  *has_valid_io_context = ((key & 1) == 0);
-  return reinterpret_cast<IOHandler*>(key & ~static_cast<ULONG_PTR>(1));
-}
-
-}  // namespace base