[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..d08fc9cbc26b743d5e1be5ce429bd5232e49e2cc 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 <queue>
 #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 enqueued global memory dump request.
+  struct GlobalMemoryDumpRequest {

[Primiano Tucci (use gerrit), 2016/06/16 08:37:23]

I'd call this QueuedMemoryDumpRequest, at first I was a bit confused why we have
this struct here. 

[petrcermak, 2016/06/16 12:08:33]

Done.

+    GlobalMemoryDumpRequest(
+        const base::trace_event::MemoryDumpRequestArgs& args,
+        const base::trace_event::MemoryDumpCallback& callback);
+    ~GlobalMemoryDumpRequest();
+    const base::trace_event::MemoryDumpRequestArgs args;
+    const base::trace_event::MemoryDumpCallback callback;
+  };
+
   TracingControllerImpl();
   ~TracingControllerImpl() override;
 
@@ -108,6 +119,10 @@ class TracingControllerImpl
     return !watch_event_callback_.is_null();
   }
 
+  void PerformGlobalMemoryDump(
+      const base::trace_event::MemoryDumpRequestArgs& args,
+      const base::trace_event::MemoryDumpCallback& callback);
+
   // Methods for use by TraceMessageFilter.
   void AddTraceMessageFilter(TraceMessageFilter* trace_message_filter);
   void RemoveTraceMessageFilter(TraceMessageFilter* trace_message_filter);
@@ -189,6 +204,7 @@ class TracingControllerImpl
   TraceMessageFilterSet pending_memory_dump_filters_;
   uint64_t pending_memory_dump_guid_;

[Primiano Tucci (use gerrit), 2016/06/16 08:37:23]

I think at this point you can get rid of pending_guid and pending_callback as
they will be just the guid and the callback of the front() of the queue.

[petrcermak, 2016/06/16 12:08:32]

Done.

   base::trace_event::MemoryDumpCallback pending_memory_dump_callback_;
+  std::queue<GlobalMemoryDumpRequest> enqueued_memory_dump_requests_;

[Primiano Tucci (use gerrit), 2016/06/16 08:37:23]

I'd drop the "en". I'm not a native speaker but "enqueued_something" sounds a
bit odd.
cs shows 6 results for \benqueued_\w+ and 135 for \bqueued_\w+ :)

[petrcermak, 2016/06/16 12:08:32]

Done, but "enqueued" sounded more posh :-P

 
   std::vector<base::trace_event::TracingAgent*> additional_tracing_agents_;
   int pending_clock_sync_ack_count_;