5 files changed, 5 insertions, 5 deletions
diff --git a/base/metrics/bucket_ranges.h b/base/metrics/bucket_ranges.h
index 90b9047..210b9a7 100644
--- a/base/metrics/bucket_ranges.h
+++ b/base/metrics/bucket_ranges.h
@@ -30,7 +30,7 @@ class BASE_EXPORT BucketRanges {
  public:
   typedef std::vector<HistogramBase::Sample> Ranges;
 
-  BucketRanges(size_t num_ranges);
+  explicit BucketRanges(size_t num_ranges);
   ~BucketRanges();
 
   size_t size() const { return ranges_.size(); }
diff --git a/base/metrics/histogram_base.h b/base/metrics/histogram_base.h
index 69e1437..949e864 100644
--- a/base/metrics/histogram_base.h
+++ b/base/metrics/histogram_base.h
@@ -69,7 +69,7 @@ class BASE_EXPORT HistogramBase {
     kHexRangePrintingFlag = 0x8000,
   };
 
-  HistogramBase(const std::string& name);
+  explicit HistogramBase(const std::string& name);
   virtual ~HistogramBase();
 
   std::string histogram_name() const { return histogram_name_; }
diff --git a/base/metrics/histogram_samples.cc b/base/metrics/histogram_samples.cc
index e375952..0e0eeb4 100644
--- a/base/metrics/histogram_samples.cc
+++ b/base/metrics/histogram_samples.cc
@@ -13,7 +13,7 @@ namespace {
 
 class SampleCountPickleIterator : public SampleCountIterator {
  public:
-  SampleCountPickleIterator(PickleIterator* iter);
+  explicit SampleCountPickleIterator(PickleIterator* iter);
 
   virtual bool Done() const OVERRIDE;
   virtual void Next() OVERRIDE;
diff --git a/base/metrics/sample_map.h b/base/metrics/sample_map.h
index 22c391bb..cdd1138 100644
--- a/base/metrics/sample_map.h
+++ b/base/metrics/sample_map.h
@@ -46,7 +46,7 @@ class BASE_EXPORT_PRIVATE SampleMapIterator : public SampleCountIterator {
   typedef std::map<HistogramBase::Sample, HistogramBase::Count>
       SampleToCountMap;
 
-  SampleMapIterator(const SampleToCountMap& sample_counts);
+  explicit SampleMapIterator(const SampleToCountMap& sample_counts);
   virtual ~SampleMapIterator();
 
   // SampleCountIterator implementation:
diff --git a/base/metrics/sparse_histogram.h b/base/metrics/sparse_histogram.h
index 346ffeb..ae4530a 100644
--- a/base/metrics/sparse_histogram.h
+++ b/base/metrics/sparse_histogram.h
@@ -46,7 +46,7 @@ class BASE_EXPORT_PRIVATE SparseHistogram : public HistogramBase {
 
  private:
   // Clients should always use FactoryGet to create SparseHistogram.
-  SparseHistogram(const std::string& name);
+  explicit SparseHistogram(const std::string& name);
 
   friend BASE_EXPORT_PRIVATE HistogramBase* DeserializeHistogramInfo(
       PickleIterator* iter);