remove redundant DCHECK that a size_t variable >= 0

base/metrics/sample_vector.cc

Index: base/metrics/sample_vector.cc
diff --git a/base/metrics/sample_vector.cc b/base/metrics/sample_vector.cc
index f90d80bd38759a803656413e3d3d145e4443a5b0..8f1451035ecce1a97acd9dd60d50e5a39e033554 100644
--- a/base/metrics/sample_vector.cc
+++ b/base/metrics/sample_vector.cc
@@ -43,7 +43,7 @@ Count SampleVector::TotalCount() const {
 }
 
 Count SampleVector::GetCountAtIndex(size_t bucket_index) const {
-  DCHECK(bucket_index >= 0 && bucket_index < counts_.size());
+  DCHECK(bucket_index < counts_.size());
   return counts_[bucket_index];
 }