trace: redirect logs to trace based on policy

If trace is enabled for component than an attempt to put message into
trace buffer is performed using log_output policy. If it succeeds than
message is not put to logs using log service.

Fixes #3714

repos/base/include/base/thread.h

@@ -417,6 +417,16 @@ class Genode::Thread
 			_logger()->log(cstring, strlen(cstring));
 		}
 
+		/**
+		 * Log null-terminated string as trace event using log_output policy
+		 *
+		 * \return true if trace is really put to buffer
+		 */
+		static bool trace_captured(char const *cstring)
+		{
+			return _logger()->log_captured(cstring, strlen(cstring));
+		}
+
 		/**
 		 * Log binary data as trace event
 		 */

repos/base/include/base/trace/logger.h

@@ -67,6 +67,13 @@ struct Genode::Trace::Logger
 		 */
 		void log(char const *, size_t);
 
+		/**
+		 * Log binary data to trace buffer using log_output policy
+		 *
+		 * \return true if log is really put to buffer
+		 */
+		bool log_captured(char const *, size_t);
+
 		/**
 		 * Log event to trace buffer
 		 */