using ulp to improve TranslateManager GetTargetLanguage() and InitiateTranslation()

components/translate/core/browser/translate_manager.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_MANAGER_H_
 #define COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_MANAGER_H_
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback_list.h"
+#include "base/feature_list.h"
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "components/translate/core/browser/language_state.h"
 #include "components/translate/core/common/translate_errors.h"
 
 class GURL;
 class PrefService;
 
 namespace translate {
 
+// Feature flag for "Translate Language by ULP" project.

[groby-ooo-7-16, 2016/08/04 02:33:42]

You can probably skip this comment - it says nothing the code doesn't say.

[ftang, 2016/08/05 04:45:27]

Done.

+extern const base::Feature kTranslateLanguageByULP;
+
 class TranslateClient;
 class TranslateDriver;
 class TranslatePrefs;
 struct TranslateErrorDetails;
 
 // The TranslateManager class is responsible for showing an info-bar when a page
 // in a language different than the user language is loaded.  It triggers the
 // page translation the user requests.
 
 class TranslateManager {
@@ skipping 11 matching lines @@
   // Cannot return NULL.
   TranslateClient* translate_client() { return translate_client_; }
 
   // Sets the sequence number of the current page, for use while sending
   // messages to the renderer.
   void set_current_seq_no(int page_seq_no) { page_seq_no_ = page_seq_no; }
 
   // Returns the language to translate to. The language returned is the
   // first language found in the following list that is supported by the
   // translation service:
+  //     High confidence and high probability reading language in ULP
   //     the UI language
   //     the accept-language list
   // If no language is found then an empty string is returned.
   static std::string GetTargetLanguage(const TranslatePrefs* prefs);
 
   // Returns the language to automatically translate to. |original_language| is
   // the webpage's original language.
   static std::string GetAutoTargetLanguage(const std::string& original_language,
                                            TranslatePrefs* translate_prefs);
 
@@ skipping 31 matching lines @@
   RegisterTranslateErrorCallback(const TranslateErrorCallback& callback);
 
   // Gets the LanguageState associated with the TranslateManager
   LanguageState& GetLanguageState();
 
   // By default, don't offer to translate in builds lacking an API key. For
   // testing, set to true to offer anyway.
   static void SetIgnoreMissingKeyForTesting(bool ignore);
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(TranslateManagerTest, TestGetTargetLanguageFromULP);
+  FRIEND_TEST_ALL_PREFIXES(TranslateManagerTest, TestLanguageInULP);
+
   // Sends a translation request to the TranslateDriver.
   void DoTranslatePage(const std::string& translate_script,
                        const std::string& source_lang,
                        const std::string& target_lang);
 
+  // Returns the language to translate to by looking at ULP. Return empty string
+  // If it cannot conclude from ULP.
+  static std::string GetTargetLanguageFromULP(const TranslatePrefs* prefs);
+
+  // Return true if the language is in the ULP with high confidence and high
+  // probability.
+  bool LanguageInULP(const TranslatePrefs* prefs,
+                     const std::string& language) const;
+
   // Notifies all registered callbacks of translate errors.
   void NotifyTranslateError(TranslateErrors::Type error_type);
 
   // Called when the Translate script has been fetched.
   // Initiates the translation.
   void OnTranslateScriptFetchComplete(const std::string& source_lang,
                                       const std::string& target_lang,
                                       bool success,
                                       const std::string& data);
 
@@ skipping 13 matching lines @@
   // By default, don't offer to translate in builds lacking an API key. For
   // testing, set to true to offer anyway.
   static bool ignore_missing_key_for_testing_;
 
   DISALLOW_COPY_AND_ASSIGN(TranslateManager);
 };
 
 }  // namespace translate
 
 #endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_MANAGER_H_