DCHECK fix for https://codereview.webrtc.org/1769113003/

TBR=stefan@webrtc.org

BUG=webrtc:5514

Review URL: https://codereview.webrtc.org/1770373002 .

Cr-Commit-Position: refs/heads/master@{#11905}
diff --git a/webrtc/modules/video_coding/histogram.cc b/webrtc/modules/video_coding/histogram.cc
index 057e1f1..e07d50b 100644
--- a/webrtc/modules/video_coding/histogram.cc
+++ b/webrtc/modules/video_coding/histogram.cc
@@ -25,7 +25,6 @@
 }
 
 void Histogram::Add(size_t value) {
-  RTC_DCHECK_GE(value, 0u);
   value = std::min<size_t>(value, buckets_.size() - 1);
   if (index_ < values_.size()) {
     --buckets_[values_[index_]];