[tracing] Introduce "allowed_dump_modes" for memory dump config

base/trace_event/trace_config_unittest.cc

 // Copyright 2015 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.
 
 #include <stddef.h>
 
 #include "base/json/json_reader.h"
 #include "base/macros.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/trace_config.h"
@@ skipping 17 matching lines @@
   "{"
     "\"enable_argument_filter\":true,"
     "\"enable_sampling\":true,"
     "\"enable_systrace\":true,"
     "\"excluded_categories\":[\"excluded\",\"exc_pattern*\"],"
     "\"included_categories\":[\"included\","
                             "\"inc_pattern*\","
                             "\"disabled-by-default-cc\","
                             "\"disabled-by-default-memory-infra\"],"
     "\"memory_dump_config\":{"
+      "\"allowed_dump_modes\":[\"background\",\"light\",\"detailed\"],"
       "\"heap_profiler_options\":{"
         "\"breakdown_threshold_bytes\":10240"
       "},"
       "\"triggers\":["
         "{\"mode\":\"light\",\"periodic_interval_ms\":50},"
         "{\"mode\":\"detailed\",\"periodic_interval_ms\":1000}"
       "]"
     "},"
     "\"record_mode\":\"record-continuously\","
     "\"synthetic_delays\":[\"test.Delay1;16\",\"test.Delay2;32\"]"
@@ skipping 627 matching lines @@
   EXPECT_NE(std::string::npos, tc.ToString().find("memory_dump_config"));
   EXPECT_EQ(2u, tc.memory_dump_config_.triggers.size());
   EXPECT_EQ(TraceConfig::MemoryDumpConfig::HeapProfiler
             ::kDefaultBreakdownThresholdBytes,
             tc.memory_dump_config_.heap_profiler_options
             .breakdown_threshold_bytes);
 }
 
 }  // namespace trace_event
 }  // namespace base