[Sync] Record sync memory usage in histogram broken by datatypes

components/sync/base/data_type_histogram.cc

Index: components/sync/base/data_type_histogram.cc
diff --git a/components/sync/base/data_type_histogram.cc b/components/sync/base/data_type_histogram.cc
index b8be026a135c73a5aecefd2b73b43b50f3b9111e..8934d1f60991e3dce37c4fd0f1977fa890660ea1 100644
--- a/components/sync/base/data_type_histogram.cc
+++ b/components/sync/base/data_type_histogram.cc
@@ -4,6 +4,7 @@
 
 #include "components/sync/base/data_type_histogram.h"
 
+#include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 
 void SyncRecordDatatypeBin(const std::string& name, int sample, int value) {
@@ -11,3 +12,17 @@ void SyncRecordDatatypeBin(const std::string& name, int sample, int value) {
       name, base::HistogramBase::kUmaTargetedHistogramFlag);
   histogram->AddCount(sample, value);
 }
+
+void SyncRecordMemoryKbHistogram(const std::string& histogram_name_prefix,
+                                 syncer::ModelType model_type,
+                                 size_t value) {
+  std::string type_string;
+  if (RealModelTypeToNotificationType(model_type, &type_string)) {
+    std::string full_histogram_name = histogram_name_prefix + type_string;
+    base::HistogramBase* histogram = base::Histogram::FactoryGet(
+        full_histogram_name, 1, 500000, 50,
+        base::HistogramBase::kUmaTargetedHistogramFlag);
+    if (histogram)
+      histogram->Add(value);
+  }
+}