FBTF: Moves code to the headers.

base/histogram.h

Index: base/histogram.h
diff --git a/base/histogram.h b/base/histogram.h
index adf673c679b68a8a29adcd5aae9c834ef0ab34f4..0287d3770ca6eb4baaa10131b418b14b9509526d 100644
--- a/base/histogram.h
+++ b/base/histogram.h
@@ -272,6 +272,8 @@ class Histogram : public base::RefCountedThreadSafe<Histogram> {
   class SampleSet {
    public:
     explicit SampleSet();
+    ~SampleSet();
+
     // Adjust size of counts_ for use with given histogram.
     void Resize(const Histogram& histogram);
     void CheckSize(const Histogram& histogram) const;
@@ -490,6 +492,8 @@ class LinearHistogram : public Histogram {
       base::TimeDelta minimum, base::TimeDelta maximum, size_t bucket_count,
       Flags flags);
 
+  virtual ~LinearHistogram();
+
  protected:
   LinearHistogram(const std::string& name, Sample minimum,
                   Sample maximum, size_t bucket_count);