WTF: Remove WTF::MutexBase::Locked.

It has been superseded by AssertAcquired.

Bug: 856641
Change-Id: Iebb6ea251dc4102ec3cb5b2a46f80afeedeb462c
Reviewed-on: https://chromium-review.googlesource.com/1201349Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588416}

third_party/blink/renderer/platform/heap/persistent_node.cc

@@ -198,7 +198,7 @@ void CrossThreadPersistentRegion::PrepareForThreadStateTermination(
 #if defined(ADDRESS_SANITIZER)
 void CrossThreadPersistentRegion::UnpoisonCrossThreadPersistents() {
 #if DCHECK_IS_ON()
-  DCHECK(ProcessHeap::CrossThreadPersistentMutex().Locked());
+  ProcessHeap::CrossThreadPersistentMutex().AssertAcquired();
 #endif
   int persistent_count = 0;
   for (PersistentNodeSlots* slots = persistent_region_.slots_; slots;

third_party/blink/renderer/platform/heap/persistent_node.h

@@ -183,7 +183,7 @@ class CrossThreadPersistentRegion final {
 
   void FreePersistentNode(PersistentNode*& persistent_node) {
 #if DCHECK_IS_ON()
-    DCHECK(ProcessHeap::CrossThreadPersistentMutex().Locked());
+    ProcessHeap::CrossThreadPersistentMutex().AssertAcquired();
 #endif
     // When the thread that holds the heap object that the cross-thread
     // persistent shuts down, prepareForThreadStateTermination() will clear out

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

@@ -71,14 +71,11 @@ class WTF_EXPORT MutexBase {
 
   void lock();
   void unlock();
+  void AssertAcquired() const {
 #if DCHECK_IS_ON()
-  // Deprecated in favour of AssertAcquired.
-  bool Locked() const { return mutex_.recursion_count_ > 0; }
-
-  void AssertAcquired() const { DCHECK(Locked()); }
-#else
-  void AssertAcquired() const {}
+    DCHECK(mutex_.recursion_count_);
 #endif
+  }
 
  public:
   PlatformMutex& Impl() { return mutex_; }