Revert of [tracing] Display the locked size of discardable memory segment.

base/memory/discardable_shared_memory.cc

Index: base/memory/discardable_shared_memory.cc
diff --git a/base/memory/discardable_shared_memory.cc b/base/memory/discardable_shared_memory.cc
index d0eaca1a66219eafee72db30d3e91170e4055e98..0f85c1fe903d612ecf055043c1a0d84d362ddbf7 100644
--- a/base/memory/discardable_shared_memory.cc
+++ b/base/memory/discardable_shared_memory.cc
@@ -340,15 +340,6 @@
          !result.GetTimestamp().is_null();
 }
 
-bool DiscardableSharedMemory::IsMemoryLocked() const {
-  DCHECK(shared_memory_.memory());
-
-  SharedState result(subtle::NoBarrier_Load(
-      &SharedStateFromSharedMemory(shared_memory_)->value.i));
-
-  return result.GetLockState() == SharedState::LOCKED;
-}
-
 void DiscardableSharedMemory::Close() {
   shared_memory_.Close();
 }