[tracing] Don't register tracing-related allocations.

base/trace_event/malloc_dump_provider.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/trace_event/malloc_dump_provider.h"
 
 #include <stddef.h>
 
 #include "base/allocator/allocator_extension.h"
 #include "base/allocator/allocator_shim.h"
@@ skipping 279 matching lines @@
       tid_dumping_heap_ == PlatformThread::CurrentId())
     return;
 
   // AllocationContextTracker will return nullptr when called re-reentrantly.
   // This is the case of GetInstanceForCurrentThread() being called for the
   // first time, which causes a new() inside the tracker which re-enters the
   // heap profiler, in which case we just want to early out.
   auto* tracker = AllocationContextTracker::GetInstanceForCurrentThread();
   if (!tracker)
     return;
-  AllocationContext context = tracker->GetContextSnapshot();
+
+  AllocationContext context;
+  if (!tracker->GetContextSnapshot(&context))
+    return;
 
   AutoLock lock(allocation_register_lock_);
   if (!allocation_register_)
     return;
 
   allocation_register_->Insert(address, size, context);
 }
 
 void MallocDumpProvider::RemoveAllocation(void* address) {
   // No re-entrancy is expected here as none of the calls below should
   // cause a free()-s (|allocation_register_| does its own heap management).
   if (tid_dumping_heap_ != kInvalidThreadId &&
       tid_dumping_heap_ == PlatformThread::CurrentId())
     return;
   AutoLock lock(allocation_register_lock_);
   if (!allocation_register_)
     return;
   allocation_register_->Remove(address);
 }
 
 }  // namespace trace_event
 }  // namespace base