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/base/platform_thread.cc

@@ -0,0 +1,82 @@
+/*
+ *  Copyright (c) 2015 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/base/platform_thread.h"
+
+#include <string.h>
+
+#include "webrtc/base/checks.h"
+
+#if defined(WEBRTC_LINUX)
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+#endif
+
+namespace rtc {
+
+PlatformThreadId CurrentThreadId() {
+  PlatformThreadId ret;
+#if defined(WEBRTC_WIN)
+  ret = GetCurrentThreadId();
+#elif defined(WEBRTC_POSIX)
+#if defined(WEBRTC_MAC) || defined(WEBRTC_IOS)
+  ret = pthread_mach_thread_np(pthread_self());
+#elif defined(WEBRTC_LINUX)
+  ret =  syscall(__NR_gettid);
+#elif defined(WEBRTC_ANDROID)
+  ret = gettid();
+#else
+  // Default implementation for nacl and solaris.
+  ret = reinterpret_cast<pid_t>(pthread_self());
+#endif
+#endif  // defined(WEBRTC_POSIX)
+  RTC_DCHECK(ret);
+  return ret;
+}
+
+PlatformThreadRef CurrentThreadRef() {
+#if defined(WEBRTC_WIN)
+  return GetCurrentThreadId();
+#elif defined(WEBRTC_POSIX)
+  return pthread_self();
+#endif
+}
+
+bool IsThreadRefEqual(const PlatformThreadRef& a, const PlatformThreadRef& b) {
+#if defined(WEBRTC_WIN)
+  return a == b;
+#elif defined(WEBRTC_POSIX)
+  return pthread_equal(a, b);
+#endif
+}
+
+void SetCurrentThreadName(const char* name) {
+  RTC_DCHECK(strlen(name) < 64);
+#if defined(WEBRTC_WIN)
+  struct {
+    DWORD dwType;
+    LPCSTR szName;
+    DWORD dwThreadID;
+    DWORD dwFlags;
+  } threadname_info = {0x1000, name, static_cast<DWORD>(-1), 0};
+
+  __try {
+    ::RaiseException(0x406D1388, 0, sizeof(threadname_info) / sizeof(DWORD),
+                     reinterpret_cast<ULONG_PTR*>(&threadname_info));
+  } __except (EXCEPTION_EXECUTE_HANDLER) {
+  }
+#elif defined(WEBRTC_LINUX) || defined(WEBRTC_ANDROID)
+  prctl(PR_SET_NAME, reinterpret_cast<unsigned long>(name));
+#elif defined(WEBRTC_MAC) || defined(WEBRTC_IOS)
+  pthread_setname_np(name);
+#endif
+}
+
+}  // namespace rtc