[tracing] Fix HostDiscardable dump provider to register on the right thread

content/common/host_discardable_shared_memory_manager.cc

Index: content/common/host_discardable_shared_memory_manager.cc
diff --git a/content/common/host_discardable_shared_memory_manager.cc b/content/common/host_discardable_shared_memory_manager.cc
index c8e793fa89beeed94e331459a5b6688da27ddbeb..f862bbc00340b40bcd9e1afffa16a0ab08de7de7 100644
--- a/content/common/host_discardable_shared_memory_manager.cc
+++ b/content/common/host_discardable_shared_memory_manager.cc
@@ -177,7 +177,8 @@ HostDiscardableSharedMemoryManager::HostDiscardableSharedMemoryManager()
       base::Bind(&HostDiscardableSharedMemoryManager::EnforceMemoryPolicy,
                  weak_ptr_factory_.GetWeakPtr());
   base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
-      this, "HostDiscardableSharedMemoryManager", nullptr);
+      this, "HostDiscardableSharedMemoryManager",
+      base::ThreadTaskRunnerHandle::Get());
 }
 
 HostDiscardableSharedMemoryManager::~HostDiscardableSharedMemoryManager() {