[IndexedDB] Adding txn, value, and key size metrics

content/browser/indexed_db/indexed_db_transaction.cc

Index: content/browser/indexed_db/indexed_db_transaction.cc
diff --git a/content/browser/indexed_db/indexed_db_transaction.cc b/content/browser/indexed_db/indexed_db_transaction.cc
index 904a284651a5220be85d53d13c6958292ac8756c..6e104bba59e8302ecda615e0a0cf12e289b45325 100644
--- a/content/browser/indexed_db/indexed_db_transaction.cc
+++ b/content/browser/indexed_db/indexed_db_transaction.cc
@@ -8,6 +8,7 @@
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ -336,6 +337,9 @@ leveldb::Status IndexedDBTransaction::CommitPhaseTwo() {
 
   state_ = FINISHED;
 
+  UMA_HISTOGRAM_MEMORY_KB("WebCore.IndexedDB.Transaction.SizeOnCommit",
+                          transaction_->transaction()->GetTransactionSize());
+
   leveldb::Status s;
   bool committed;
   if (!used_) {
@@ -350,6 +354,8 @@ leveldb::Status IndexedDBTransaction::CommitPhaseTwo() {
   // release references and allow the backing store itself to be
   // released, and order is critical.
   CloseOpenCursors();
+  UMA_HISTOGRAM_MEMORY_KB("WebCore.IndexedDB.TransactionSize",

[pwnall, 2017/05/23 23:01:09]

Is this number different because of the blob journal changes in CommitPhaseTwo?
Can you please add a comment explaining?

[dmurph, 2017/05/24 02:01:58]

Had this wrong - put in right spot now, with comment.

+                          transaction_->transaction()->GetTransactionSize());
   transaction_->Reset();
 
   // Transactions must also be marked as completed before the