Histogram type support in HistogramBase and remove SetRangeDescription function

base/metrics/histogram_base.h

Index: base/metrics/histogram_base.h
diff --git a/base/metrics/histogram_base.h b/base/metrics/histogram_base.h
index 5e27e1e4bfe63bd289468288bd436f706384795a..302795a73fc7a4072bb4fc26ccb86461a5f790c0 100644
--- a/base/metrics/histogram_base.h
+++ b/base/metrics/histogram_base.h
@@ -14,9 +14,25 @@
 namespace base {
 
 class DictionaryValue;
+class HistogramSamples;
 class ListValue;
 
-class HistogramSamples;
+////////////////////////////////////////////////////////////////////////////////
+// These enums are used to facilitate deserialization of histograms from other
+// processes into the browser. If you create another class that inherits from
+// HistogramBase, add new histogram types and names below.
+
+enum BASE_EXPORT HistogramType {
+  HISTOGRAM,
+  LINEAR_HISTOGRAM,
+  BOOLEAN_HISTOGRAM,
+  CUSTOM_HISTOGRAM,
+  SPARSE_HISTOGRAM,
+};
+
+std::string HistogramTypeToString(HistogramType type);
+
+////////////////////////////////////////////////////////////////////////////////
 
 class BASE_EXPORT HistogramBase {
  public:
@@ -40,7 +56,6 @@ class BASE_EXPORT HistogramBase {
     kHexRangePrintingFlag = 0x8000,
   };
 
-
   HistogramBase(const std::string& name);
   virtual ~HistogramBase();
 
@@ -51,6 +66,8 @@ class BASE_EXPORT HistogramBase {
   void SetFlags(int32 flags);
   void ClearFlags(int32 flags);
 
+  virtual HistogramType GetHistogramType() const = 0;
+
   // Whether the histogram has construction arguments as parameters specified.
   // For histograms that don't have the concept of minimum, maximum or
   // bucket_count, this function always returns false.