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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/base/task/task_runner.h"
#include "base/metrics/histogram_functions.h"
#include "base/no_destructor.h"
#include "base/rand_util.h"
#include "base/task/single_thread_task_runner.h"
namespace net {
namespace {
base::MetricsSubSampler& GetMetricsSubSampler() {
static base::MetricsSubSampler sampler;
return sampler;
}
} // namespace
const scoped_refptr<base::SingleThreadTaskRunner>& GetTaskRunner(
RequestPriority priority) {
// Sample with a 0.001 probability to reduce metrics overhead.
if (GetMetricsSubSampler().ShouldSample(0.001)) {
base::UmaHistogramEnumeration("Net.TaskRunner.RequestPriority", priority);
}
if (internal::GetTaskRunnerGlobals().task_runners[priority]) {
return internal::GetTaskRunnerGlobals().task_runners[priority];
}
// Fall back to the default task runner if the embedder does not inject one,
// for example, when the NetworkServiceTaskScheduler feature is disabled.
return base::SingleThreadTaskRunner::GetCurrentDefault();
}
namespace internal {
TaskRunnerGlobals::TaskRunnerGlobals() = default;
TaskRunnerGlobals::~TaskRunnerGlobals() = default;
TaskRunnerGlobals& GetTaskRunnerGlobals() {
static base::NoDestructor<TaskRunnerGlobals> globals;
return *globals;
}
} // namespace internal
} // namespace net
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