Reuse ThreadData instances associated with terminated named threads.

components/metrics/profiler/tracking_synchronizer_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 "components/metrics/profiler/tracking_synchronizer.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/macros.h"
@@ skipping 51 matching lines @@
     switch (attributes.profiling_phase) {
       case 0:
         EXPECT_FALSE(got_phase_0_);
         got_phase_0_ = true;
 
         EXPECT_EQ(base::TimeTicks() + base::TimeDelta::FromMilliseconds(111),
                   attributes.phase_start);
         EXPECT_EQ(base::TimeTicks() + base::TimeDelta::FromMilliseconds(333),
                   attributes.phase_finish);
 
-        EXPECT_EQ("death_thread0",
-                  process_data_phase.tasks[0].death_thread_name);
+        EXPECT_EQ("death_threadA",
+                  process_data_phase.tasks[0].death_sanitized_thread_name);
         EXPECT_EQ(0u, past_events.size());
         break;
 
       case 1:
         EXPECT_FALSE(got_phase_1_);
         got_phase_1_ = true;
 
         EXPECT_EQ(base::TimeTicks() + base::TimeDelta::FromMilliseconds(333),
                   attributes.phase_start);
         EXPECT_EQ(base::TimeTicks() + base::TimeDelta::FromMilliseconds(777),
                   attributes.phase_finish);
 
-        EXPECT_EQ("death_thread1",
-                  process_data_phase.tasks[0].death_thread_name);
+        EXPECT_EQ("death_threadB",
+                  process_data_phase.tasks[0].death_sanitized_thread_name);
         ASSERT_EQ(1u, past_events.size());
         EXPECT_EQ(ProfilerEventProto::EVENT_FIRST_NONEMPTY_PAINT,
                   past_events[0]);
         break;
 
       default:
         bool profiling_phase_is_neither_0_nor_1 = true;
         EXPECT_FALSE(profiling_phase_is_neither_0_nor_1);
     }
   }
@@ skipping 30 matching lines @@
       new TestTrackingSynchronizer(base::WrapUnique(clock));
 
   clock->Advance(base::TimeDelta::FromMilliseconds(222));
 
   tracking_synchronizer->RegisterPhaseCompletion(
       ProfilerEventProto::EVENT_FIRST_NONEMPTY_PAINT);
 
   tracked_objects::ProcessDataSnapshot profiler_data;
   ProcessDataPhaseSnapshot snapshot0;
   tracked_objects::TaskSnapshot task_snapshot0;
-  task_snapshot0.death_thread_name = "death_thread0";
+  task_snapshot0.death_sanitized_thread_name = "death_threadA";
   snapshot0.tasks.push_back(task_snapshot0);
   ProcessDataPhaseSnapshot snapshot1;
   profiler_data.phased_snapshots[0] = snapshot0;
   tracked_objects::TaskSnapshot task_snapshot1;
-  task_snapshot1.death_thread_name = "death_thread1";
+  task_snapshot1.death_sanitized_thread_name = "death_threadB";
   snapshot1.tasks.push_back(task_snapshot1);
   profiler_data.phased_snapshots[1] = snapshot1;
   profiler_data.process_id = 239;
 
   clock->Advance(base::TimeDelta::FromMilliseconds(444));
   TestObserver test_observer;
   tracking_synchronizer->SendData(
       profiler_data, ProfilerEventProto::TrackedObject::PPAPI_PLUGIN,
       &test_observer);
 }
 
 }  // namespace metrics