Integrate RankerModelLoader with TranslateRanker.

chrome/browser/translate/translate_ranker_metrics_provider.cc

Index: chrome/browser/translate/translate_ranker_metrics_provider.cc
diff --git a/chrome/browser/translate/translate_ranker_metrics_provider.cc b/chrome/browser/translate/translate_ranker_metrics_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ba98a639a5fa96c621120d1812414fecc52f5f08
--- /dev/null
+++ b/chrome/browser/translate/translate_ranker_metrics_provider.cc
@@ -0,0 +1,35 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/translate/translate_ranker_metrics_provider.h"
+
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/translate/translate_ranker_factory.h"
+#include "components/metrics/proto/chrome_user_metrics_extension.pb.h"
+#include "components/metrics/proto/translate_event.pb.h"
+#include "components/translate/core/browser/translate_ranker.h"
+
+namespace translate {
+
+void TranslateRankerMetricsProvider::ProvideGeneralMetrics(
+    metrics::ChromeUserMetricsExtension* uma_proto) {
+  std::vector<Profile*> loaded_profiles =
+      g_browser_process->profile_manager()->GetLoadedProfiles();

[emaxx, 2017/04/04 13:22:38]

Note that on Chrome OS there is a special sign-in profile which doesn't
correspond to any user session - it's used for hosting the login screen
controls. (Technically speaking, there are actually two profiles: one is the
Default profile and another is the incognito profile derived from it. Different
parts of Chrome choose themselves which one they want to use.)

So is this the expected behavior to track these UMA metrics for this profile?

In case it's not, then it should be probably checked here - e.g. using the
chromeos::ProfileHelper::IsSigninProfile method. Also the similar guard may need
to be added into TranslateRankerFactory (but, again, I don't know what is really
required for your feature).

[Roger McFarlane (Chromium), 2017/04/04 17:03:06]

As long as I get back a valid set of profile pointers without triggering a
profile load (while missing the credentials to open the profile) I think I'm ok.
The events will only be populated for profiles the user is actively using to
browse; it should be fine if I grab the "special" profiles... they'll just have
an empty event cache.

[emaxx, 2017/04/04 17:12:38]

Thanks for the clarification.

+  for (Profile* profile : loaded_profiles) {
+    TranslateRanker* ranker =
+        TranslateRankerFactory::GetForBrowserContext(profile);
+    if (!ranker)
+      return;
+
+    std::vector<metrics::TranslateEventProto> translate_events;
+    ranker->FlushTranslateEvents(&translate_events);
+
+    for (auto& event : translate_events) {
+      uma_proto->add_translate_event()->Swap(&event);
+    }
+  }
+}
+
+}  // namespace translate