Return a copy, becase GetPercentile in SamplesStatsCounter isn't const

Bug: webrtc:10138
Change-Id: I2ec2ce4765e514bfd065f094f5905233e5f4f9cd
Reviewed-on: https://webrtc-review.googlesource.com/c/123043
Reviewed-by: Peter Slatala <psla@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26697}
diff --git a/test/pc/e2e/analyzer/video/default_video_quality_analyzer.cc b/test/pc/e2e/analyzer/video/default_video_quality_analyzer.cc
index 9828540..c3bf685 100644
--- a/test/pc/e2e/analyzer/video/default_video_quality_analyzer.cc
+++ b/test/pc/e2e/analyzer/video/default_video_quality_analyzer.cc
@@ -316,13 +316,13 @@
   return stream_frame_counters_;
 }
 
-const std::map<std::string, StreamStats>&
-DefaultVideoQualityAnalyzer::GetStats() const {
+std::map<std::string, StreamStats> DefaultVideoQualityAnalyzer::GetStats()
+    const {
   rtc::CritScope cri(&comparison_lock_);
   return stream_stats_;
 }
 
-const AnalyzerStats& DefaultVideoQualityAnalyzer::GetAnalyzerStats() const {
+AnalyzerStats DefaultVideoQualityAnalyzer::GetAnalyzerStats() const {
   rtc::CritScope crit(&comparison_lock_);
   return analyzer_stats_;
 }
diff --git a/test/pc/e2e/analyzer/video/default_video_quality_analyzer.h b/test/pc/e2e/analyzer/video/default_video_quality_analyzer.h
index 2e28829..570253d 100644
--- a/test/pc/e2e/analyzer/video/default_video_quality_analyzer.h
+++ b/test/pc/e2e/analyzer/video/default_video_quality_analyzer.h
@@ -145,8 +145,8 @@
   const std::map<std::string, FrameCounters>& GetPerStreamCounters() const;
   // Returns video quality stats per stream label. Valid stream labels can be
   // obtained by calling GetKnownVideoStreams()
-  const std::map<std::string, StreamStats>& GetStats() const;
-  const AnalyzerStats& GetAnalyzerStats() const;
+  std::map<std::string, StreamStats> GetStats() const;
+  AnalyzerStats GetAnalyzerStats() const;
 
  private:
   struct FrameStats {