Reuse ThreadData instances associated with terminated named threads.

components/metrics/profiler/profiler_metrics_provider.cc

Index: components/metrics/profiler/profiler_metrics_provider.cc
diff --git a/components/metrics/profiler/profiler_metrics_provider.cc b/components/metrics/profiler/profiler_metrics_provider.cc
index 2ab8c0314f6712ddfe9e48ce2c154ed5a56cab7f..0e83e94ab23f3a7104ce34a37bec5241877277dd 100644
--- a/components/metrics/profiler/profiler_metrics_provider.cc
+++ b/components/metrics/profiler/profiler_metrics_provider.cc
@@ -4,7 +4,6 @@
 
 #include "components/metrics/profiler/profiler_metrics_provider.h"
 
-#include <ctype.h>
 #include <stddef.h>
 #include <string>
 #include <vector>
@@ -16,23 +15,6 @@
 namespace metrics {
 namespace {
 
-// Maps a thread name by replacing trailing sequence of digits with "*".
-// Examples:
-// 1. "BrowserBlockingWorker1/23857" => "BrowserBlockingWorker1/*"
-// 2. "Chrome_IOThread" => "Chrome_IOThread"
-std::string MapThreadName(const std::string& thread_name) {
-  size_t i = thread_name.length();
-
-  while (i > 0 && isdigit(thread_name[i - 1])) {
-    --i;
-  }
-
-  if (i == thread_name.length())
-    return thread_name;
-
-  return thread_name.substr(0, i) + '*';
-}
-
 // Normalizes a source filename (which is platform- and build-method-dependent)
 // by extracting the last component of the full file name.
 // Example: "c:\b\build\slave\win\build\src\chrome\app\chrome_main.cc" =>
@@ -52,9 +34,9 @@ void WriteProfilerData(
     ProfilerEventProto::TrackedObject* tracked_object =
         performance_profile->add_tracked_object();
     tracked_object->set_birth_thread_name_hash(
-        MetricsLog::Hash(MapThreadName(task.birth.thread_name)));
+        MetricsLog::Hash(task.birth.thread_name));
     tracked_object->set_exec_thread_name_hash(
-        MetricsLog::Hash(MapThreadName(task.death_thread_name)));
+        MetricsLog::Hash(task.death_thread_name));
     tracked_object->set_source_file_name_hash(
         MetricsLog::Hash(NormalizeFileName(task.birth.location.file_name)));
     tracked_object->set_source_function_name_hash(