Measuring data use of different ModelTypes in Sync Service.

sync/engine/syncer_unittest.cc

Index: sync/engine/syncer_unittest.cc
diff --git a/sync/engine/syncer_unittest.cc b/sync/engine/syncer_unittest.cc
index dcd326e8c887888ddab0eb867fafb20be8a07bcb..8559731a9dded8c4fb1e021eefbd1efbd94b211f 100644
--- a/sync/engine/syncer_unittest.cc
+++ b/sync/engine/syncer_unittest.cc
@@ -20,6 +20,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/test/histogram_tester.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "sync/engine/backoff_delay_provider.h"
@@ -666,6 +667,61 @@ TEST_F(SyncerTest, GetCommitIdsFiltersThrottledEntries) {
   }
 }
 
+// This test is based on SyncerTest.GetCommitIdsFiltersThrottledEntries. After
+// different steps in that test, the progress is verified against expected
+// progress.
+TEST_F(SyncerTest, DataUseHistogramsTest) {
+  base::HistogramTester histogram_tester;
+  const ModelTypeSet throttled_types(BOOKMARKS);
+  sync_pb::EntitySpecifics bookmark_data;
+  AddDefaultFieldValue(BOOKMARKS, &bookmark_data);
+
+  mock_server_->AddUpdateDirectory(1, 0, "A", 10, 10,
+                                   foreign_cache_guid(), "-1");
+  EXPECT_TRUE(SyncShareNudge());
+  {
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Upload.Count", 0);

[sclittle, 2015/08/14 19:10:59]

Instead of ExpectTotalCount, could you use ExpectUniqueSample or
ExpectBucketCount on the BOOKMARKS type or something?

[amohammadkhan, 2015/08/17 17:56:16]

Done.

+    histogram_tester.ExpectTotalCount("DataUse.Sync.Upload.Bytes", 0);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Download.Count", 1);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Download.Bytes", 63);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.ProgressMarker.Bytes", 84);
+    WriteTransaction wtrans(FROM_HERE, UNITTEST, directory());
+    MutableEntry A(&wtrans, GET_BY_ID, ids_.FromNumber(1));
+    A.PutIsUnsynced(true);
+    A.PutSpecifics(bookmark_data);
+    A.PutNonUniqueName("bookmark");
+  }
+
+  // Now sync without enabling bookmarks.
+  mock_server_->ExpectGetUpdatesRequestTypes(
+      Difference(context_->GetEnabledTypes(), ModelTypeSet(BOOKMARKS)));
+  ResetSession();
+  syncer_->NormalSyncShare(
+      Difference(context_->GetEnabledTypes(), ModelTypeSet(BOOKMARKS)),
+      &nudge_tracker_, session_.get());
+
+  {
+    // Nothing should have been committed as bookmarks is throttled.
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Upload.Count", 0);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Upload.Bytes", 0);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Download.Count", 1);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Download.Bytes", 63);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.ProgressMarker.Bytes", 140);
+  }
+
+  // Sync again with bookmarks enabled.
+  mock_server_->ExpectGetUpdatesRequestTypes(context_->GetEnabledTypes());
+  EXPECT_TRUE(SyncShareNudge());
+  {
+    // It should have been committed.
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Upload.Count", 1);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Upload.Bytes", 91);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Download.Count", 1);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.Download.Bytes", 63);
+    histogram_tester.ExpectTotalCount("DataUse.Sync.ProgressMarker.Bytes", 224);
+  }
+}
+
 // We use a macro so we can preserve the error location.
 #define VERIFY_ENTRY(id, is_unapplied, is_unsynced, prev_initialized, \
                      parent_id, version, server_version, id_fac, rtrans) \