Measuring data use of different ModelTypes in Sync Service.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index ab7289663c8bd358271c1fab318dd23364b30a2f..99d50b054f0bde787f7e0bd84d4c2061616dd0de 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -5212,6 +5212,46 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="DataUse.Sync.Download.Bytes" enum="SyncModelTypes">
+  <owner>amohammadkhan@chromium.org</owner>
+  <summary>
+    Number of downloaded bytes of different data types in Sync service for
+    received updates.
+  </summary>
+</histogram>
+
+<histogram name="DataUse.Sync.Download.Count" enum="SyncModelTypes">
+  <owner>amohammadkhan@chromium.org</owner>
+  <summary>
+    Number of downloaded entities of different data types in Sync service for
+    received updates.
+  </summary>
+</histogram>
+
+<histogram name="DataUse.Sync.ProgressMarker.Bytes" enum="SyncModelTypes">
+  <owner>amohammadkhan@chromium.org</owner>
+  <summary>
+    Number of downloaded bytes of ProgressMarker of different data types in Sync
+    service for received updates.
+  </summary>
+</histogram>
+
+<histogram name="DataUse.Sync.Upload.Bytes" enum="SyncModelTypes">
+  <owner>amohammadkhan@chromium.org</owner>
+  <summary>
+    Number of uploaded bytes of different data types in Sync service for sent
+    commits.
+  </summary>
+</histogram>
+
+<histogram name="DataUse.Sync.Upload.Count" enum="SyncModelTypes">
+  <owner>amohammadkhan@chromium.org</owner>
+  <summary>
+    Number of uploaded entities of different data types in Sync service for sent
+    commits.
+  </summary>
+</histogram>
+
 <histogram name="DefaultBrowser.InteractionResult"
     enum="MakeChromeDefaultResult">
   <owner>gab@chromium.org</owner>