[battery] Deprecate BatterySamplingDelay

Bug: 1421844
Change-Id: I0cb28da275c587e54bd84acef72989c6392adde6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4343935
Reviewed-by: Olivier Li <olivierli@chromium.org>
Reviewed-by: Francois Pierre Doray <fdoray@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1118305}

chrome/browser/metrics/power/power_metrics_reporter.cc

@@ -29,9 +29,6 @@
 
 namespace {
 
-constexpr const char* kBatterySamplingDelayHistogramName =
-    "Power.BatterySamplingDelay";
-
 // Calculates the UKM bucket |value| falls in and returns it. This uses an
 // exponential bucketing approach with an exponent base of 1.3, resulting in
 // 17 buckets for an interval of 120 seconds.
@@ -203,8 +200,7 @@ void PowerMetricsReporter::OnAggregatedMetricsSampled(
     //       |battery_level_provider_|.
     battery_level_provider_->GetBatteryState(base::BindOnce(
         &PowerMetricsReporter::OnBatteryAndAggregatedProcessMetricsSampled,
-        base::Unretained(this), metrics, interval_duration,
-        /*battery_sample_begin_time=*/now));
+        base::Unretained(this), metrics, interval_duration));
   } else {
     // Get usage scenario data.
     auto long_interval_data =
@@ -216,17 +212,11 @@ void PowerMetricsReporter::OnAggregatedMetricsSampled(
 void PowerMetricsReporter::OnBatteryAndAggregatedProcessMetricsSampled(
     const ProcessMonitor::Metrics& aggregated_process_metrics,
     base::TimeDelta interval_duration,
-    base::TimeTicks battery_sample_begin_time,
     const absl::optional<base::BatteryLevelProvider::BatteryState>&
         new_battery_state) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(battery_level_provider_);
 
-  // Report time it took to sample the battery state.
-  base::UmaHistogramMicrosecondsTimes(
-      kBatterySamplingDelayHistogramName,
-      base::TimeTicks::Now() - battery_sample_begin_time);
-
   // Evaluate battery discharge mode and rate.
   auto previous_battery_state =
       std::exchange(battery_state_, new_battery_state);

chrome/browser/metrics/power/power_metrics_reporter.h

@@ -106,7 +106,6 @@ class PowerMetricsReporter : public ProcessMonitor::Observer {
   void OnBatteryAndAggregatedProcessMetricsSampled(
       const ProcessMonitor::Metrics& aggregated_process_metrics,
       base::TimeDelta interval_duration,
-      base::TimeTicks battery_sample_begin_time,
       const absl::optional<base::BatteryLevelProvider::BatteryState>&
           new_battery_state);
 

tools/metrics/histograms/metadata/power/histograms.xml

@@ -1145,17 +1145,6 @@ chromium-metrics-reviews@google.com.
   </summary>
 </histogram>
 
-<histogram name="Power.BatterySamplingDelay" units="microseconds"
-    expires_after="2023-04-16">
-  <owner>etiennep@chromium.org</owner>
-  <owner>fdoray@chromium.org</owner>
-  <summary>
-    The delay in microseconds between the time a battery charge level query was
-    schedule and the time the state is made available, reported everytime the
-    battery charge level is sampled. Reported for all users on Windows and Mac.
-  </summary>
-</histogram>
-
 <histogram name="Power.BitfixChunks" units="units" expires_after="M77">
   <owner>dianders@chromium.org</owner>
   <summary>