Fix overflow bug in histogram sample data structures

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 46faef068fd8ab4586ab3e937112d34d868e01ea..ccb94317250df3b6aa2f792c183b7f9d66c95656 100644
--- a/base/metrics/sample_vector.cc
+++ b/base/metrics/sample_vector.cc
@@ -43,7 +43,7 @@ void SampleVector::Accumulate(Sample value, Count count) {
   size_t bucket_index = GetBucketIndex(value);
   subtle::NoBarrier_Store(&counts_[bucket_index],
       subtle::NoBarrier_Load(&counts_[bucket_index]) + count);
-  IncreaseSum(count * value);
+  IncreaseSum(static_cast<int64_t>(count) * value);
   IncreaseRedundantCount(count);
 }