Revert "WTF: CHECK if a mutex is recursively acquired."

This reverts commit e41ffb6c.

Reason for revert: WebAudio can still do recursive acquisition due to finalizing objects during an allocation in which the lock is held. See crbug.com/882314

Original change's description:
> WTF: CHECK if a mutex is recursively acquired.
> 
> This is a final attempt to flush out any recursive acquisition
> before support is totally removed for WTF::RecursiveMutex.
> 
> For pthreads, this requires maintaining the recursion_count_
> variable even in non-DCHECK builds. This is still quite cheap,
> and is temporary in any case.
> 
> Bug: 856641
> Change-Id: I2b550fd58e8c4cf6293ad7628dd49aa366b41ae9
> Reviewed-on: https://chromium-review.googlesource.com/1212453
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Commit-Queue: Jeremy Roman <jbroman@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#589504}

TBR=jbroman@chromium.org,yutak@chromium.org,haraken@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 856641,882314
Change-Id: I1e2732ee0c810d5fed73ba29874088abaeed2d59
Reviewed-on: https://chromium-review.googlesource.com/1225297Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591130}

third_party/blink/renderer/platform/wtf/threading_primitives.h

@@ -56,7 +56,9 @@ typedef CONDITION_VARIABLE PlatformCondition;
 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
 struct PlatformMutex {
   pthread_mutex_t internal_mutex_;
+#if DCHECK_IS_ON()
   size_t recursion_count_;
+#endif
 };
 typedef pthread_cond_t PlatformCondition;
 #endif

third_party/blink/renderer/platform/wtf/threading_pthreads.cc

@@ -70,7 +70,9 @@ MutexBase::MutexBase(bool recursive) {
 
   int result = pthread_mutex_init(&mutex_.internal_mutex_, &attr);
   DCHECK_EQ(result, 0);
+#if DCHECK_IS_ON()
   mutex_.recursion_count_ = 0;
+#endif
 
   pthread_mutexattr_destroy(&attr);
 }
@@ -83,14 +85,18 @@ MutexBase::~MutexBase() {
 void MutexBase::lock() {
   int result = pthread_mutex_lock(&mutex_.internal_mutex_);
   DCHECK_EQ(result, 0);
-  CHECK(!mutex_.recursion_count_)
+#if DCHECK_IS_ON()
+  DCHECK(!mutex_.recursion_count_)
       << "WTF does not support recursive mutex acquisition!";
   ++mutex_.recursion_count_;
+#endif
 }
 
 void MutexBase::unlock() {
+#if DCHECK_IS_ON()
   DCHECK(mutex_.recursion_count_);
   --mutex_.recursion_count_;
+#endif
   int result = pthread_mutex_unlock(&mutex_.internal_mutex_);
   DCHECK_EQ(result, 0);
 }
@@ -103,11 +109,13 @@ void MutexBase::unlock() {
 bool Mutex::TryLock() {
   int result = pthread_mutex_trylock(&mutex_.internal_mutex_);
   if (result == 0) {
+#if DCHECK_IS_ON()
     // The Mutex class is not recursive, so the recursionCount should be
     // zero after getting the lock.
-    CHECK(!mutex_.recursion_count_)
+    DCHECK(!mutex_.recursion_count_)
         << "WTF does not support recursive mutex acquisition!";
     ++mutex_.recursion_count_;
+#endif
     return true;
   }
   if (result == EBUSY)
@@ -120,9 +128,11 @@ bool Mutex::TryLock() {
 bool RecursiveMutex::TryLock() {
   int result = pthread_mutex_trylock(&mutex_.internal_mutex_);
   if (result == 0) {
-    CHECK(!mutex_.recursion_count_)
+#if DCHECK_IS_ON()
+    DCHECK(!mutex_.recursion_count_)
         << "WTF does not support recursive mutex acquisition!";
     ++mutex_.recursion_count_;
+#endif
     return true;
   }
   if (result == EBUSY)
@@ -142,10 +152,14 @@ ThreadCondition::~ThreadCondition() {
 
 void ThreadCondition::Wait() {
   base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
+#if DCHECK_IS_ON()
   --mutex_.recursion_count_;
+#endif
   int result = pthread_cond_wait(&condition_, &mutex_.internal_mutex_);
   DCHECK_EQ(result, 0);
+#if DCHECK_IS_ON()
   ++mutex_.recursion_count_;
+#endif
 }
 
 void ThreadCondition::Signal() {

third_party/blink/renderer/platform/wtf/threading_win.cc

@@ -122,7 +122,7 @@ MutexBase::~MutexBase() {
 
 void MutexBase::lock() {
   EnterCriticalSection(&mutex_.internal_mutex_);
-  CHECK(!mutex_.recursion_count_)
+  DCHECK(!mutex_.recursion_count_)
       << "WTF does not support recursive mutex acquisition!";
   ++mutex_.recursion_count_;
 }
@@ -149,7 +149,7 @@ bool Mutex::TryLock() {
     // check in the lock method (presumably due to performance?). This
     // means lock() will succeed even if the current thread has already
     // entered the critical section.
-    CHECK(!mutex_.recursion_count_)
+    DCHECK(!mutex_.recursion_count_)
         << "WTF does not support recursive mutex acquisition!";
     if (mutex_.recursion_count_ > 0) {
       LeaveCriticalSection(&mutex_.internal_mutex_);
@@ -169,7 +169,7 @@ bool RecursiveMutex::TryLock() {
   if (result == 0) {  // We didn't get the lock.
     return false;
   }
-  CHECK(!mutex_.recursion_count_)
+  DCHECK(!mutex_.recursion_count_)
       << "WTF does not support recursive mutex acquisition!";
   ++mutex_.recursion_count_;
   return true;