Change from custom Lock to std::mutex.

Rest of merge of http://go/wvgerrit/67884
Some files were deleted on original CL that were not deleted here.

Now that we can use C++11, we should use the cross-platform std::mutex
type, not the custom pthread version.

Bug: 111850982
Test: WV unit/integration tests
Change-Id: I48a1e47aa79e5e66b5869c0f766c18d561d26784

libwvdrmengine/cdm/util/include/lock.h

@@ -1,53 +0,0 @@
-// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
-// source code may only be used and distributed under the Widevine Master
-// License Agreement.
-//
-// Lock - Platform independent interface for a Mutex class
-//
-#ifndef WVCDM_UTIL_LOCK_H_
-#define WVCDM_UTIL_LOCK_H_
-
-#include "disallow_copy_and_assign.h"
-
-namespace wvcdm {
-
-// Simple lock class. The implementation is platform dependent.
-//
-// The lock must be unlocked by the thread that locked it.
-// The lock is also not recursive (ie. cannot be taken multiple times).
-class Lock {
- public:
-  Lock();
-  ~Lock();
-
-  void Acquire();
-  void Release();
-
-  friend class AutoLock;
-
- private:
-  class Impl;
-  Impl* impl_;
-
-  CORE_DISALLOW_COPY_AND_ASSIGN(Lock);
-};
-
-// Manages the lock automatically. It will be locked when AutoLock
-// is constructed and release when AutoLock goes out of scope.
-class AutoLock {
- public:
-  explicit AutoLock(Lock& lock) : lock_(&lock) { lock_->Acquire(); }
-
-  explicit AutoLock(Lock* lock) : lock_(lock) { lock_->Acquire(); }
-
-  ~AutoLock() { lock_->Release(); }
-
- private:
-  Lock* lock_;
-
-  CORE_DISALLOW_COPY_AND_ASSIGN(AutoLock);
-};
-
-}  // namespace wvcdm
-
-#endif  // WVCDM_UTIL_LOCK_H_

libwvdrmengine/cdm/util/src/lock.cpp

@@ -1,32 +0,0 @@
-// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
-// source code may only be used and distributed under the Widevine Master
-// License Agreement.
-//
-// Lock class - provides a simple android specific mutex implementation
-
-#include "lock.h"
-#include <utils/Mutex.h>
-
-namespace wvcdm {
-
-class Lock::Impl {
- public:
-  android::Mutex lock_;
-};
-
-Lock::Lock() : impl_(new Lock::Impl()) {
-}
-
-Lock::~Lock() {
-  delete impl_;
-}
-
-void Lock::Acquire() {
-  impl_->lock_.lock();
-}
-
-void Lock::Release() {
-  impl_->lock_.unlock();
-}
-
-}  // namespace wvcdm