[tracing] Add SkResourceCache as suballocation to avoid double counting.

content/child/child_discardable_shared_memory_manager.cc

Index: content/child/child_discardable_shared_memory_manager.cc
diff --git a/content/child/child_discardable_shared_memory_manager.cc b/content/child/child_discardable_shared_memory_manager.cc
index 5bdcef7337279443eb335df5bdde37cdbd926d88..617669157f38b69a052eb2c0512749cc57bc9d7a 100644
--- a/content/child/child_discardable_shared_memory_manager.cc
+++ b/content/child/child_discardable_shared_memory_manager.cc
@@ -192,6 +192,13 @@ ChildDiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(
 
 bool ChildDiscardableSharedMemoryManager::OnMemoryDump(
     base::trace_event::ProcessMemoryDump* pmd) {
+  base::trace_event::MemoryAllocatorDump* objects_dump =
+      pmd->CreateAllocatorDump(GetMemoryPoolNameForTracing());
+  base::trace_event::MemoryAllocatorDump* discardable_segments_dump =
+      pmd->CreateAllocatorDump("discardable/segments");
+  pmd->AddOwnershipEdge(objects_dump->guid(),
+                        discardable_segments_dump->guid());
+
   base::AutoLock lock(lock_);
   return heap_.OnMemoryDump(pmd);
 }