Logging: check for filter before sending to the queue, to skip all heavy formatting on the other thread.

src/common/logging/backend.h

@@ -10,6 +10,7 @@
 
 #include "common/concurrent_ring_buffer.h"
 
+#include "common/logging/filter.h"
 #include "common/logging/log.h"
 
 namespace Log {
@@ -131,4 +132,6 @@ Entry CreateEntry(Class log_class, Level log_level,
 /// Initializes the default Logger.
 std::shared_ptr<Logger> InitGlobalLogger();
 
+void SetFilter(Filter* filter);
+
 }