[translate] Add translate ranker model loader.

components/translate/core/browser/translate_manager.cc

Index: components/translate/core/browser/translate_manager.cc
diff --git a/components/translate/core/browser/translate_manager.cc b/components/translate/core/browser/translate_manager.cc
index 33d3c514a5d011646e21b4c5aedfbff7679a21f6..07766c732d67c87f27fd5c4a98c72e04611b941a 100644
--- a/components/translate/core/browser/translate_manager.cc
+++ b/components/translate/core/browser/translate_manager.cc
@@ -131,17 +131,16 @@ TranslateManager::RegisterTranslateErrorCallback(
 
 TranslateManager::TranslateManager(
     TranslateClient* translate_client,
+    TranslateRanker* translate_ranker,
     const std::string& accept_languages_pref_name)
     : page_seq_no_(0),
       accept_languages_pref_name_(accept_languages_pref_name),
       translate_client_(translate_client),
       translate_driver_(translate_client_->GetTranslateDriver()),
+      translate_ranker_(translate_ranker),
       language_state_(translate_driver_),
       translate_event_(base::MakeUnique<metrics::TranslateEventProto>()),
-      weak_method_factory_(this) {
-  if (TranslateRanker::IsEnabled())
-    TranslateRanker::GetInstance()->FetchModelData();  // Asynchronous.
-}
+      weak_method_factory_(this) {}
 
 base::WeakPtr<TranslateManager> TranslateManager::GetWeakPtr() {
   return weak_method_factory_.GetWeakPtr();
@@ -230,6 +229,19 @@ void TranslateManager::InitiateTranslation(const std::string& page_lang) {
     return;
   }
 
+  bool ranker_should_offer_translation = true;

[groby-ooo-7-16, 2017/01/23 21:41:57]

Shouldn't this be initialized to false? If it doesn't enter the is-enabled
block, it shouldn't really offer translation?

[Roger McFarlane (Chromium), 2017/02/08 23:08:11]

In it's current incarnation, the ranker is as gate, not a trigger. I the ranker
is not enabled and/or it's enforcement is not enabled, the default/existing
behavior is to show the prompt, subject to the various other limiting heuristics
below.

To make it clearer, I've gotten rid of the generic IsEnabled() and retained just
the specific IsQueryEnabled(), IsEnforcementEnabled(), IsLoggingEnabled()
methods..

+  if (translate_ranker_->IsEnabled()) {
+    ranker_should_offer_translation = translate_ranker_->ShouldOfferTranslation(
+        *translate_prefs, language_code, target_lang);
+    translate_event_->set_ranker_request_timestamp_sec(
+        (base::TimeTicks::Now() - base::TimeTicks()).InSeconds());
+    translate_event_->set_ranker_version(translate_ranker_->GetModelVersion());
+    translate_event_->set_ranker_response(
+        ranker_should_offer_translation
+            ? metrics::TranslateEventProto::SHOW
+            : metrics::TranslateEventProto::DONT_SHOW);
+  }
+
   // Nothing to do if either the language Chrome is in or the language of the
   // page is not supported by the translation server.
   if (target_lang.empty() ||
@@ -300,22 +312,12 @@ void TranslateManager::InitiateTranslation(const std::string& page_lang) {
     return;
   }
 
-  if (TranslateRanker::IsEnabled()) {
-    TranslateRanker* translate_ranker = TranslateRanker::GetInstance();
-    bool should_offer_translation = translate_ranker->ShouldOfferTranslation(
-        *translate_prefs, language_code, target_lang);
-    translate_event_->set_ranker_request_timestamp_sec(
-        (base::TimeTicks::Now() - base::TimeTicks()).InSeconds());
-    translate_event_->set_ranker_version(translate_ranker->GetModelVersion());
-    translate_event_->set_ranker_response(
-        should_offer_translation ? metrics::TranslateEventProto::SHOW
-                                 : metrics::TranslateEventProto::DONT_SHOW);
-    if (!should_offer_translation && TranslateRanker::IsEnforcementEnabled()) {
-      TranslateBrowserMetrics::ReportInitiationStatus(
-          TranslateBrowserMetrics::INITIATION_STATUS_ABORTED_BY_RANKER);
-      RecordTranslateEvent(metrics::TranslateEventProto::DISABLED_BY_RANKER);
-      return;
-    }
+  if (!ranker_should_offer_translation &&
+      translate_ranker_->IsEnforcementEnabled()) {
+    TranslateBrowserMetrics::ReportInitiationStatus(
+        TranslateBrowserMetrics::INITIATION_STATUS_ABORTED_BY_RANKER);
+    RecordTranslateEvent(metrics::TranslateEventProto::DISABLED_BY_RANKER);
+    return;
   }
 
   TranslateBrowserMetrics::ReportInitiationStatus(
@@ -601,7 +603,8 @@ void TranslateManager::RecordTranslateEvent(int event_type) {
       static_cast<metrics::TranslateEventProto::EventType>(event_type));
   translate_event_->set_event_timestamp_sec(
       (base::TimeTicks::Now() - base::TimeTicks()).InSeconds());
-  TranslateRanker::GetInstance()->RecordTranslateEvent(*translate_event_);
+  translate_ranker_->AddTranslateEvent(std::move(translate_event_));
+  translate_event_ = base::MakeUnique<metrics::TranslateEventProto>();
 }
 
 }  // namespace translate