PartitionAllocMemoryDumpProvider can directly inherit from MemoryDumpProvider

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 eabe50ee216205740fb5be052be89febecc502fa..cf69859404e5a0b2694540d82e4f29461cdaea0f 100644
--- a/base/trace_event/malloc_dump_provider.cc
+++ b/base/trace_event/malloc_dump_provider.cc
@@ -192,13 +192,7 @@ bool MallocDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
         allocation_register_->EstimateTraceMemoryOverhead(&overhead);
       }
     }  // lock(allocation_register_lock_)
-
-    if (!metrics_by_context.empty()) {
-      std::unique_ptr<TracedValue> heap_dump = ExportHeapDump(
-          metrics_by_context, *pmd->session_state());
-      pmd->AddHeapDump("malloc", std::move(heap_dump));
-    }
-    overhead.DumpInto("tracing/heap_profiler_malloc", pmd);
+    pmd->DumpHeapUsage(metrics_by_context, overhead, "malloc");
   }
   tid_dumping_heap_ = kInvalidThreadId;