Serialize/Deserialize support in HistogramBase

base/metrics/histogram_base.cc

Index: base/metrics/histogram_base.cc
diff --git a/base/metrics/histogram_base.cc b/base/metrics/histogram_base.cc
index bcfb57feb231ce7be9b31bbf4eb34b0e8b441b0d..63961327a0422fdc9ef75f2f2e160459c8f1afcc 100644
--- a/base/metrics/histogram_base.cc
+++ b/base/metrics/histogram_base.cc
@@ -9,6 +9,10 @@
 #include "base/logging.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_samples.h"
+#include "base/metrics/sparse_histogram.h"
+#include "base/pickle.h"
 #include "base/values.h"
 
 namespace base {
@@ -31,6 +35,41 @@ std::string HistogramTypeToString(HistogramType type) {
   return "UNKNOWN";
 }
 
+HistogramBase* DeserializeHistogramInfo(PickleIterator* iter) {
+  int type;
+  if (!iter->ReadInt(&type))
+    return NULL;
+
+  switch (type) {
+    case HISTOGRAM:
+      return Histogram::DeserializeInfoImpl(iter);
+    case LINEAR_HISTOGRAM:
+      return LinearHistogram::DeserializeInfoImpl(iter);
+    case BOOLEAN_HISTOGRAM:
+      return BooleanHistogram::DeserializeInfoImpl(iter);
+    case CUSTOM_HISTOGRAM:
+      return CustomHistogram::DeserializeInfoImpl(iter);
+    case SPARSE_HISTOGRAM:
+      return SparseHistogram::DeserializeInfoImpl(iter);
+    default:
+      return NULL;
+  }
+}
+
+void DeserializeHistogramAndAddSamples(PickleIterator* iter) {
+  HistogramBase* histogram = DeserializeHistogramInfo(iter);
+  if (!histogram)
+    return;
+
+  if (histogram->flags() & base::HistogramBase::kIPCSerializationSourceFlag) {
+    DVLOG(1) << "Single process mode, histogram observed and not copied: "
+             << histogram->histogram_name();
+    return;
+  }
+  histogram->AddSamplesFromPickle(iter);
+}
+
+
 const HistogramBase::Sample HistogramBase::kSampleType_MAX = INT_MAX;
 
 HistogramBase::HistogramBase(const std::string& name)
@@ -47,6 +86,12 @@ void HistogramBase::ClearFlags(int32 flags) {
   flags_ &= ~flags;
 }
 
+bool HistogramBase::SerializeInfo(Pickle* pickle) const {
+  if (!pickle->WriteInt(GetHistogramType()))
+    return false;
+  return SerializeInfoImpl(pickle);
+}
+
 void HistogramBase::WriteJSON(std::string* output) const {
   Count count;
   scoped_ptr<ListValue> buckets(new ListValue());