Fix crash in InvokeOnMemoryDump when tracing

base/trace_event/memory_dump_manager.cc

Index: base/trace_event/memory_dump_manager.cc
diff --git a/base/trace_event/memory_dump_manager.cc b/base/trace_event/memory_dump_manager.cc
index 31016f970e3155cd18d749595d5dc432d38c5486..a2b5ed342ec152c0d5a42f1b54f529cf6244bdff 100644
--- a/base/trace_event/memory_dump_manager.cc
+++ b/base/trace_event/memory_dump_manager.cc
@@ -483,6 +483,17 @@ void MemoryDumpManager::RequestGlobalDump(
   RequestGlobalDump(dump_type, level_of_detail, MemoryDumpCallback());
 }
 
+bool MemoryDumpManager::IsDumpProviderRegisteredForTesting(
+    MemoryDumpProvider* provider) {
+  AutoLock lock(lock_);
+
+  for (const auto& info : dump_providers_) {
+    if (info->dump_provider == provider)
+      return true;
+  }
+  return false;
+}
+
 void MemoryDumpManager::CreateProcessDump(const MemoryDumpRequestArgs& args,
                                           const MemoryDumpCallback& callback) {
   TRACE_EVENT_NESTABLE_ASYNC_BEGIN0(kTraceCategory, "ProcessMemoryDump",