Update audio_processing module

Corresponds to upstream commit 524e9b043e7e86fd72353b987c9d5f6a1ebf83e1

Update notes:

 * Pull in third party license file

 * Replace .gypi files with BUILD.gn to keep track of what changes
   upstream

 * Bunch of new filse pulled in as dependencies

 * Won't build yet due to changes needed on top of these

webrtc/system_wrappers/source/event_timer_win.cc

@@ -0,0 +1,78 @@
+/*
+ *  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 "webrtc/system_wrappers/source/event_timer_win.h"
+
+#include "Mmsystem.h"
+
+namespace webrtc {
+
+// static
+EventTimerWrapper* EventTimerWrapper::Create() {
+  return new EventTimerWin();
+}
+
+EventTimerWin::EventTimerWin()
+    : event_(::CreateEvent(NULL,    // security attributes
+                           FALSE,   // manual reset
+                           FALSE,   // initial state
+                           NULL)),  // name of event
+    timerID_(NULL) {
+}
+
+EventTimerWin::~EventTimerWin() {
+  StopTimer();
+  CloseHandle(event_);
+}
+
+bool EventTimerWin::Set() {
+  // Note: setting an event that is already set has no effect.
+  return SetEvent(event_) == 1;
+}
+
+EventTypeWrapper EventTimerWin::Wait(unsigned long max_time) {
+  unsigned long res = WaitForSingleObject(event_, max_time);
+  switch (res) {
+    case WAIT_OBJECT_0:
+      return kEventSignaled;
+    case WAIT_TIMEOUT:
+      return kEventTimeout;
+    default:
+      return kEventError;
+  }
+}
+
+bool EventTimerWin::StartTimer(bool periodic, unsigned long time) {
+  if (timerID_ != NULL) {
+    timeKillEvent(timerID_);
+    timerID_ = NULL;
+  }
+
+  if (periodic) {
+    timerID_ = timeSetEvent(time, 0, (LPTIMECALLBACK)HANDLE(event_), 0,
+                            TIME_PERIODIC | TIME_CALLBACK_EVENT_PULSE);
+  } else {
+    timerID_ = timeSetEvent(time, 0, (LPTIMECALLBACK)HANDLE(event_), 0,
+                            TIME_ONESHOT | TIME_CALLBACK_EVENT_SET);
+  }
+
+  return timerID_ != NULL;
+}
+
+bool EventTimerWin::StopTimer() {
+  if (timerID_ != NULL) {
+    timeKillEvent(timerID_);
+    timerID_ = NULL;
+  }
+
+  return true;
+}
+
+}  // namespace webrtc