Remove worker pool names from TaskScheduler.TaskLatency.* histograms.

base/task_scheduler/task_tracker.h

Index: base/task_scheduler/task_tracker.h
diff --git a/base/task_scheduler/task_tracker.h b/base/task_scheduler/task_tracker.h
index a5caf213985ea20bd986cafb70bea32d76891207..14ca1f419329dc9cb890eab9e9693f5419d8d250 100644
--- a/base/task_scheduler/task_tracker.h
+++ b/base/task_scheduler/task_tracker.h
@@ -21,13 +21,15 @@
 namespace base {
 
 class ConditionVariable;
+class HistogramBase;
 class SequenceToken;
 
 namespace internal {
 
 // All tasks go through the scheduler's TaskTracker when they are posted and
-// when they are executed. The TaskTracker enforces shutdown semantics and takes
-// care of tracing and profiling. This class is thread-safe.
+// when they are executed. The TaskTracker sets up the environment to run tasks,
+// enforces shutdown semantics, records metrics, and takes care of tracing and
+// profiling. This class is thread-safe.
 class BASE_EXPORT TaskTracker {
  public:
   TaskTracker();
@@ -106,6 +108,10 @@ class BASE_EXPORT TaskTracker {
   // it reaches zero.
   void DecrementNumPendingUndelayedTasks();
 
+  // Records the TaskScheduler.TaskLatency.[task priority].[may block] histogram
+  // for |task|.
+  void RecordTaskLatencyHistogram(Task* task);
+
   // Number of tasks blocking shutdown and boolean indicating whether shutdown
   // has started.
   const std::unique_ptr<State> state_;
@@ -133,6 +139,12 @@ class BASE_EXPORT TaskTracker {
   // completes.
   std::unique_ptr<WaitableEvent> shutdown_event_;
 
+  // TaskScheduler.TaskLatency.[task priority].[may block] histograms. The first
+  // index is a TaskPriority. The second index is 0 for non-blocking tasks, 1
+  // for blocking tasks. Intentionally leaked.
+  HistogramBase* const
+      task_latency_histograms_[static_cast<int>(TaskPriority::HIGHEST) + 1][2];
+
   // Number of BLOCK_SHUTDOWN tasks posted during shutdown.
   HistogramBase::Sample num_block_shutdown_tasks_posted_during_shutdown_ = 0;