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

content/common/host_discardable_shared_memory_manager.cc

Index: content/common/host_discardable_shared_memory_manager.cc
diff --git a/content/common/host_discardable_shared_memory_manager.cc b/content/common/host_discardable_shared_memory_manager.cc
index 8af1d4dcc09912c2a6569fec88df88a33e54a0d7..97351e5510538dd3fc1cbb6cdf0fbce27b5d5c0b 100644
--- a/content/common/host_discardable_shared_memory_manager.cc
+++ b/content/common/host_discardable_shared_memory_manager.cc
@@ -180,16 +180,9 @@
           "discardable/process_%x/segment_%d", child_process_id, segment_id);
       base::trace_event::MemoryAllocatorDump* dump =
           pmd->CreateAllocatorDump(dump_name);
-
       dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                       base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                       segment->memory()->mapped_size());
-
-      // Host can only tell if whole segment is locked or not.
-      dump->AddScalar(
-          "locked_size", base::trace_event::MemoryAllocatorDump::kUnitsBytes,
-          segment->memory()->IsMemoryLocked() ? segment->memory()->mapped_size()
-                                              : 0u);
 
       // Create the cross-process ownership edge. If the child creates a
       // corresponding dump for the same segment, this will avoid to