Switch a couple places from trunc/floor to round.

It looks like rounding would reduce overall error in these spots.

Bug: none
Change-Id: I473aa9dac00e454ae2ec344bf554928ce9236a27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2345287Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Commit-Queue: Frank Liberato <liberato@chromium.org>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796725}

media/cast/sender/congestion_control.cc

@@ -20,6 +20,7 @@
 
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "media/cast/constants.h"
 
@@ -414,8 +415,8 @@ int AdaptiveCongestionControl::GetBitrate(base::TimeTicks playout_time,
   empty_buffer_fraction = std::min(empty_buffer_fraction, 1.0);
   empty_buffer_fraction = std::max(empty_buffer_fraction, 0.0);
 
-  int bits_per_second = static_cast<int>(
-      safe_bitrate * empty_buffer_fraction / kTargetEmptyBufferFraction);
+  int bits_per_second = base::ClampRound(safe_bitrate * empty_buffer_fraction /
+                                         kTargetEmptyBufferFraction);
   VLOG(3) << " FBR:" << (bits_per_second / 1E6)
           << " EBF:" << empty_buffer_fraction
           << " SBR:" << (safe_bitrate / 1E6);

media/filters/ffmpeg_demuxer.cc

@@ -16,6 +16,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
@@ -1225,7 +1226,7 @@ static int CalculateBitrate(AVFormatContext* format_context,
   // larger than ~1073GB.
   double bytes = filesize_in_bytes;
   double duration_us = duration.InMicroseconds();
-  return bytes * 8000000.0 / duration_us;
+  return base::ClampRound(bytes * 8000000.0 / duration_us);
 }
 
 void FFmpegDemuxer::OnOpenContextDone(bool result) {

third_party/blink/renderer/core/frame/local_frame_ukm_aggregator.cc

@@ -5,6 +5,7 @@
 #include "third_party/blink/renderer/core/frame/local_frame_ukm_aggregator.h"
 
 #include "base/format_macros.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/rand_util.h"
 #include "base/time/default_tick_clock.h"
 #include "cc/metrics/begin_main_frame_metrics.h"
@@ -336,8 +337,8 @@ void LocalFrameUkmAggregator::RecordEndOfFrameMetrics(
   }
 
   for (auto& record : main_frame_percentage_records_) {
-    unsigned percentage =
-        (unsigned)floor(record.interval_duration.InMicrosecondsF() * 100.0 /
+    auto percentage = base::ClampRound<base::HistogramBase::Sample>(
+        record.interval_duration.InMicrosecondsF() * 100.0 /
         duration.InMicrosecondsF());
     record.uma_counters_per_bucket[bucket_index]->Count(percentage);
   }
@@ -390,9 +391,9 @@ void LocalFrameUkmAggregator::UpdateSample(
   for (unsigned i = 0; i < static_cast<unsigned>(kCount); ++i) {
     current_sample_.sub_metrics_durations[i] =
         absolute_metric_records_[i].interval_duration;
-    current_sample_.sub_metric_percentages[i] = static_cast<unsigned>(floor(
+    current_sample_.sub_metric_percentages[i] = base::ClampRound<unsigned>(
         main_frame_percentage_records_[i].interval_duration.InMicrosecondsF() *
-        100.0 / primary_metric_in_microseconds));
+        100.0 / primary_metric_in_microseconds);
   }
   current_sample_.trackers = trackers;
 }

third_party/blink/renderer/core/frame/local_frame_ukm_aggregator_test.cc

@@ -61,7 +61,7 @@ class LocalFrameUkmAggregatorTest : public testing::Test {
   void VerifyUpdateEntry(unsigned index,
                          unsigned expected_primary_metric,
                          unsigned expected_sub_metric,
-                         unsigned expected_percentage,
+                         float expected_percentage,
                          unsigned expected_reasons,
                          bool expected_before_fcp) {
     auto entries = recorder().GetEntriesByName("Blink.UpdateTime");
@@ -84,7 +84,7 @@ class LocalFrameUkmAggregatorTest : public testing::Test {
           entry, GetPercentageMetricName(i)));
       const int64_t* metric_percentage = ukm::TestUkmRecorder::GetEntryMetric(
           entry, GetPercentageMetricName(i));
-      EXPECT_NEAR(*metric_percentage, expected_percentage, 0.001);
+      EXPECT_NEAR(*metric_percentage, expected_percentage, 0.5);
     }
     EXPECT_TRUE(
         ukm::TestUkmRecorder::EntryHasMetric(entry, "MainFrameIsBeforeFCP"));
@@ -185,7 +185,7 @@ TEST_F(LocalFrameUkmAggregatorTest, FirstFrameIsRecorded) {
       millisecond_for_step * LocalFrameUkmAggregator::kCount;
   float expected_sub_metric = millisecond_for_step;
   float expected_percentage =
-      floor(100.0 / static_cast<float>(LocalFrameUkmAggregator::kCount));
+      100.0 / static_cast<float>(LocalFrameUkmAggregator::kCount);
 
   VerifyUpdateEntry(0u, expected_primary_metric, expected_sub_metric,
                     expected_percentage, 12, true);
@@ -214,7 +214,7 @@ TEST_F(LocalFrameUkmAggregatorTest, PreAndPostFCPAreRecorded) {
       millisecond_per_step * LocalFrameUkmAggregator::kCount;
   float expected_sub_metric = millisecond_per_step;
   float expected_percentage =
-      floor(100.0 / static_cast<float>(LocalFrameUkmAggregator::kCount));
+      100.0 / static_cast<float>(LocalFrameUkmAggregator::kCount);
 
   VerifyUpdateEntry(0u, expected_primary_metric, expected_sub_metric,
                     expected_percentage, 4, true);
@@ -237,8 +237,8 @@ TEST_F(LocalFrameUkmAggregatorTest, PreAndPostFCPAreRecorded) {
   // been recorded.
   EXPECT_EQ(recorder().entries_count(), 3u);
 
-  expected_percentage = floor(millisecond_per_step * 100.0 /
-                              static_cast<float>(millisecond_per_frame));
+  expected_percentage =
+      millisecond_per_step * 100.0 / static_cast<float>(millisecond_per_frame);
   VerifyUpdateEntry(1u, millisecond_per_frame, millisecond_per_step,
                     expected_percentage, 4, false);
 }