Delete unused class SharedExclusiveLock.

webrtc/base/sharedexclusivelock.cc

-/*
- *  Copyright 2011 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/sharedexclusivelock.h"
-
-namespace rtc {
-
-SharedExclusiveLock::SharedExclusiveLock()
-    : shared_count_is_zero_(true, true),
-      shared_count_(0) {
-}
-
-void SharedExclusiveLock::LockExclusive() {
-  cs_exclusive_.Enter();
-  shared_count_is_zero_.Wait(Event::kForever);
-}
-
-void SharedExclusiveLock::UnlockExclusive() {
-  cs_exclusive_.Leave();
-}
-
-void SharedExclusiveLock::LockShared() {
-  CritScope exclusive_scope(&cs_exclusive_);
-  CritScope shared_scope(&cs_shared_);
-  if (++shared_count_ == 1) {
-    shared_count_is_zero_.Reset();
-  }
-}
-
-void SharedExclusiveLock::UnlockShared() {
-  CritScope shared_scope(&cs_shared_);
-  if (--shared_count_ == 0) {
-    shared_count_is_zero_.Set();
-  }
-}
-
-}  // namespace rtc