[tracing] Switch to new heap dump format.

base/trace_event/malloc_dump_provider.cc

Index: base/trace_event/malloc_dump_provider.cc
diff --git a/base/trace_event/malloc_dump_provider.cc b/base/trace_event/malloc_dump_provider.cc
index 4683694d6bb60dc15a59b544dcadf639a7464e84..1f309a4f0507a78c94eedb9ec0b1ab12c197c295 100644
--- a/base/trace_event/malloc_dump_provider.cc
+++ b/base/trace_event/malloc_dump_provider.cc
@@ -242,22 +242,10 @@ bool MallocDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
   // Enclosing all the temporariy data structures in a scope, so that the heap
   // profiler does not see unabalanced malloc/free calls from these containers.
   {
-    TraceEventMemoryOverhead overhead;
-    hash_map<AllocationContext, AllocationMetrics> metrics_by_context;
-    {
-      AutoLock lock(allocation_register_lock_);
-      if (allocation_register_) {
-        if (args.level_of_detail == MemoryDumpLevelOfDetail::DETAILED) {
-          for (const auto& alloc_size : *allocation_register_) {
-            AllocationMetrics& metrics = metrics_by_context[alloc_size.context];
-            metrics.size += alloc_size.size;
-            metrics.count++;
-          }
-        }
-        allocation_register_->EstimateTraceMemoryOverhead(&overhead);
-      }
-    }  // lock(allocation_register_lock_)
-    pmd->DumpHeapUsage(metrics_by_context, overhead, "malloc");
+    AutoLock lock(allocation_register_lock_);
+    if (allocation_register_) {
+      pmd->DumpHeapUsage(*allocation_register_, "malloc");
+    }
   }
   tid_dumping_heap_ = kInvalidThreadId;