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

content/browser/tracing/tracing_controller_impl.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_
 #define CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
+#include <queue>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/lazy_instance.h"
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/tracing_agent.h"
 #include "content/public/browser/tracing_controller.h"
@@ skipping 53 matching lines @@
     virtual void OnTraceMessageFilterAdded(TraceMessageFilter* filter) = 0;
     virtual void OnTraceMessageFilterRemoved(TraceMessageFilter* filter) = 0;
   };
   void AddTraceMessageFilterObserver(TraceMessageFilterObserver* observer);
   void RemoveTraceMessageFilterObserver(TraceMessageFilterObserver* observer);
 
  private:
   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;
 
   bool can_start_tracing() const {
     return !is_tracing_;
   }
 
   bool can_stop_tracing() const {
     return is_tracing_ && !trace_data_sink_.get();
   }
 
   bool can_start_monitoring() const {
     return !is_monitoring_;
   }
 
   bool can_stop_monitoring() const {
     return is_monitoring_ && !monitoring_data_sink_.get();
   }
 
   bool can_get_trace_buffer_usage() const {
     return pending_trace_buffer_usage_callback_.is_null();
   }
 
   bool can_cancel_watch_event() const {
     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);
 
   void OnTraceDataCollected(
       const scoped_refptr<base::RefCountedString>& events_str_ptr);
 
   // Callback of TraceLog::Flush() for the local trace.
   void OnLocalTraceDataCollected(
       const scoped_refptr<base::RefCountedString>& events_str_ptr,
@@ skipping 59 matching lines @@
   // Pending acks for GetTraceLogStatus.
   int pending_trace_log_status_ack_count_;
   TraceMessageFilterSet pending_trace_log_status_filters_;
   float maximum_trace_buffer_usage_;
   size_t approximate_event_count_;
 
   // Pending acks for memory RequestGlobalDumpPoint.
   int pending_memory_dump_ack_count_;
   int failed_memory_dump_count_;
   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_;
   base::OneShotTimer clock_sync_timer_;
 
   bool is_tracing_;
   bool is_monitoring_;
 
   GetCategoriesDoneCallback pending_get_categories_done_callback_;
   GetTraceBufferUsageCallback pending_trace_buffer_usage_callback_;
 
   std::string watch_category_name_;
   std::string watch_event_name_;
   WatchEventCallback watch_event_callback_;
 
   base::ObserverList<TraceMessageFilterObserver>
       trace_message_filter_observers_;
 
   std::set<std::string> known_category_groups_;
   std::set<TracingUI*> tracing_uis_;
   scoped_refptr<TraceDataSink> trace_data_sink_;
   scoped_refptr<TraceDataSink> monitoring_data_sink_;
 
   DISALLOW_COPY_AND_ASSIGN(TracingControllerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_