[tracing] Simplify the MemoryAllocatorDump API

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 50037c41832aa67028eb733fd883579c9a89ebf8..c04b8588c276137d019bdd2bffd42e7b9e7ee5ef 100644
--- a/base/trace_event/malloc_dump_provider.cc
+++ b/base/trace_event/malloc_dump_provider.cc
@@ -29,8 +29,7 @@ bool MallocDumpProvider::OnMemoryDump(ProcessMemoryDump* pmd) {
   struct mallinfo info = mallinfo();
   DCHECK_GE(info.arena + info.hblkhd, info.uordblks);
 
-  MemoryAllocatorDump* dump =
-      pmd->CreateAllocatorDump("malloc", MemoryAllocatorDump::kRootHeap);
+  MemoryAllocatorDump* dump = pmd->CreateAllocatorDump("malloc");
   if (!dump)
     return false;
 
@@ -39,13 +38,12 @@ bool MallocDumpProvider::OnMemoryDump(ProcessMemoryDump* pmd) {
   // |arena| is 0 and the outer pages size is reported by |hblkhd|. In case of
   // dlmalloc the total is given by |arena| + |hblkhd|.
   // For more details see link: http://goo.gl/fMR8lF.
-  dump->set_physical_size_in_bytes(info.arena + info.hblkhd);
-
-  // mallinfo doesn't support any allocated object count.
-  dump->set_allocated_objects_count(0);
+  dump->AddScalar(MemoryAllocatorDump::kNameOuterSize,
+                  MemoryAllocatorDump::kUnitsBytes, info.arena + info.hblkhd);
 
   // Total allocated space is given by |uordblks|.
-  dump->set_allocated_objects_size_in_bytes(info.uordblks);
+  dump->AddScalar(MemoryAllocatorDump::kNameInnerSize,
+                  MemoryAllocatorDump::kUnitsBytes, info.uordblks);
 
   return true;
 }