[memory-infra] Add support for queueing memory dump requests in the browser process

content/browser/tracing/tracing_controller_impl.h

Index: content/browser/tracing/tracing_controller_impl.h
diff --git a/content/browser/tracing/tracing_controller_impl.h b/content/browser/tracing/tracing_controller_impl.h
index 2f344b4be35c84bdce9ead86bb45e99f3374b802..a391cdbde3436e610009c3f285954d8f379fa745 100644
--- a/content/browser/tracing/tracing_controller_impl.h
+++ b/content/browser/tracing/tracing_controller_impl.h
@@ -8,6 +8,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include <list>
 #include <set>
 #include <string>
 #include <vector>
@@ -81,6 +82,16 @@ class TracingControllerImpl
   friend struct base::DefaultLazyInstanceTraits<TracingControllerImpl>;
   friend class TraceMessageFilter;
 
+  // The arguments and callback for an queued global memory dump request.
+  struct QueuedMemoryDumpRequest {
+    QueuedMemoryDumpRequest(
+        const base::trace_event::MemoryDumpRequestArgs& args,
+        const base::trace_event::MemoryDumpCallback& callback);
+    ~QueuedMemoryDumpRequest();
+    const base::trace_event::MemoryDumpRequestArgs args;
+    const base::trace_event::MemoryDumpCallback callback;
+  };
+
   TracingControllerImpl();
   ~TracingControllerImpl() override;
 
@@ -108,6 +119,8 @@ class TracingControllerImpl
     return !watch_event_callback_.is_null();
   }
 
+  void PerformNextQueuedGlobalMemoryDump();
+
   // Methods for use by TraceMessageFilter.
   void AddTraceMessageFilter(TraceMessageFilter* trace_message_filter);
   void RemoveTraceMessageFilter(TraceMessageFilter* trace_message_filter);
@@ -187,8 +200,7 @@ class TracingControllerImpl
   int pending_memory_dump_ack_count_;
   int failed_memory_dump_count_;
   TraceMessageFilterSet pending_memory_dump_filters_;
-  uint64_t pending_memory_dump_guid_;
-  base::trace_event::MemoryDumpCallback pending_memory_dump_callback_;
+  std::list<QueuedMemoryDumpRequest> queued_memory_dump_requests_;
 
   std::vector<base::trace_event::TracingAgent*> additional_tracing_agents_;
   int pending_clock_sync_ack_count_;