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

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 85b7dd528ba3e534bf70b569730d23877dcbec24..4d3064bd2c954f21d096408925c22116c3abcf20 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -75562,6 +75562,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Sync.ModelTypeMemoryKB" units="KB">
+  <owner>pavely@chromium.org</owner>
+  <summary>
+    Estimated memory usage by sync datatype in kilobytes. Recorded after sync
+    configuration.
+  </summary>
+</histogram>
+
 <histogram name="Sync.ModelTypeStoreInitResult"
     enum="SyncModelTypeStoreInitResult">
   <owner>pavely@chromium.org</owner>
@@ -95561,6 +95569,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <suffix name="USER_EVENT" label="USER_EVENT"/>
   <suffix name="WIFI_CREDENTIAL" label="WIFI_CREDENTIAL"/>
   <affected-histogram name="Sync.ModelTypeCount"/>
+  <affected-histogram name="Sync.ModelTypeMemoryKB"/>
 </histogram_suffixes>
 
 <histogram_suffixes name="SyzygyStartupTime" separator="_">