IndexedDB: Measure the total database open time.

content/browser/indexed_db/indexed_db_callbacks.h

Index: content/browser/indexed_db/indexed_db_callbacks.h
diff --git a/content/browser/indexed_db/indexed_db_callbacks.h b/content/browser/indexed_db/indexed_db_callbacks.h
index 4ae10a9bef69beed0a5f2a43782c5f282438da54..133fad243594cbc17a3fefa1fd2b90c20a1155d5 100644
--- a/content/browser/indexed_db/indexed_db_callbacks.h
+++ b/content/browser/indexed_db/indexed_db_callbacks.h
@@ -106,6 +106,8 @@ class CONTENT_EXPORT IndexedDBCallbacks
 
   blink::WebIDBDataLoss data_loss() const { return data_loss_; }
 
+  void SetDatbaseOpenStartTime(const base::TimeTicks& start_time);

[jsbell, 2014/08/14 22:58:05]

Typo: 'Datbase'

+
  protected:
   virtual ~IndexedDBCallbacks();
 
@@ -135,6 +137,7 @@ class CONTENT_EXPORT IndexedDBCallbacks
 
   // The "blocked" event should be sent at most once per request.
   bool sent_blocked_;
+  base::TimeTicks db_open_start_time_;

[jsbell, 2014/08/14 22:58:05]

Nit: Maybe 'connection' instead of 'db'?

That would apply to other names as well. (e.g. Database -> Connection)

[jsbell, 2014/08/14 22:58:06]

I just noticed that these were base::TimeTicks instead of base::Time - does that
play well with the UMA stats? (It looks like operators return TimeTicks rather
than TimeDeltas)

[Ilya Sherman, 2014/08/14 23:00:13]

TimeTicks is usually preferred, as it's at least guaranteed to be monotonically
non-decreasing.  TimeDelta is just a difference between time values -- it works
with both Time and TimeTicks.

[cmumford, 2014/08/14 23:53:03]

Done.

   DISALLOW_COPY_AND_ASSIGN(IndexedDBCallbacks);
 };