New thin layer of API extension chrome.i18n.detectLanguage

chrome/browser/extensions/api/i18n/i18n_api.h

 // Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_API_I18N_I18N_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_I18N_I18N_API_H_
 
+#include <string>
+#include <vector>
+
 #include "chrome/browser/extensions/chrome_extension_function.h"
 #include "extensions/browser/browser_context_keyed_api_factory.h"
+#include "extensions/browser/extension_function.h"
+#include "third_party/cld_2/src/public/compact_lang_det.h"
+#include "third_party/cld_2/src/public/encodings.h"
 
 class Profile;
 
 namespace extensions {
 
 class I18nGetAcceptLanguagesFunction : public ChromeSyncExtensionFunction {
   ~I18nGetAcceptLanguagesFunction() override {}
   bool RunSync() override;
   DECLARE_EXTENSION_FUNCTION("i18n.getAcceptLanguages", I18N_GETACCEPTLANGUAGES)
 };
 
+class I18nDetectLanguageFunction : public UIThreadExtensionFunction {
+ public:
+  // Results returned by CLD
+  struct DetectedLanguage {

[not at google - send to devlin, 2015/07/10 16:21:09]

You shouldn't need to make this public, and in fact, ideally you'd be able to
forward-declare them (I can't remember if linked_ptr<DetectedLanguage> is
forward-declaration friendly, worth a shot though).

... and all that said, really, this should already be generated for you in
out/Debug/gen/chrome/common/extensions/api/i18n.h

you #include it with #include "chrome/common/extensions/api/i18n.h"

[amalika, 2015/07/10 18:18:36]

I think we finally understand what you meant in this and comment from last
patch. Those structs are already auto generated in
"chrome/common/extensions/api/i18n.h" so there is no need to define them
ourselves and instead use them. Is that right?
If that is the case, then I would remove two structs defined here. Is it
acceptable to use typedef to make code more readable?
** typedef struct extensions::api::i18n::DetectLanguage::Results::Result
LanguageDetectionResult;


If it is a bad practice, should I just define 
** namespace LanguageDetectionResult =
extensions::api::i18n::DetectLanguage::Results;

Thank you!

[not at google - send to devlin, 2015/07/13 21:25:10]

Yep you can typedef, but only in the .cc file (not the header).

[amalika, 2015/07/13 23:57:01]

Done.

+      DetectedLanguage();
+      DetectedLanguage(std::string language, int percentage);
+      ~DetectedLanguage();
+      // Returns a new base::DictionaryValue representing the serialized form of
+      // this LanguagesType object.
+      scoped_ptr<base::DictionaryValue> ToValue() const;
+
+      std::string language;
+      int percentage;
+  };
+
+  // LanguageDetectionResult object that holds detected langugae reliability and
+  // array of DetectedLanguage
+  struct LanguageDetectionResult {

[not at google - send to devlin, 2015/07/10 16:21:09]

You should be able to define this entirely in an anonymous namespace in the .cc
file.

[amalika, 2015/07/13 23:57:01]

Acknowledged.

+      LanguageDetectionResult();
+      LanguageDetectionResult(bool is_reliable,

[not at google - send to devlin, 2015/07/10 16:21:09]

This is not the style we use, but running "git cl format" will fix that all for
you.

[amalika, 2015/07/13 23:57:01]

Done.

+          std::vector<linked_ptr<DetectedLanguage> > detected_langs);
+      ~LanguageDetectionResult();
+
+      // Returns a new base::DictionaryValue representing the serialized form of
+      // this Result object.
+      scoped_ptr<base::DictionaryValue> ToValue() const;
+
+      // CLD detected language reliability
+      bool is_reliable;
+
+      // array of detectedLanguage of size 1-3. The null is returned if
+      // there were no languages detected
+      std::vector<linked_ptr<DetectedLanguage> > detected_langs;

[not at google - send to devlin, 2015/07/10 16:21:09]

No space needed between "> >" anymore. Same goes for everywhere else that there
is a space between "> >".

[amalika, 2015/07/13 23:57:01]

Done.

+  };
+
+ private:
+  ~I18nDetectLanguageFunction() override {};
+  ResponseAction Run() override;
+  void GetLanguage(const std::string& text);
+  void SendLanguagesResult(
+       std::vector<linked_ptr<DetectedLanguage> > detected_langs,
+       bool is_reliable);
+  void InitDetectedLanguages(CLD2::Language* langs, int* percent3,
+       std::vector<linked_ptr<DetectedLanguage> >* detected_langs);
+
+  DECLARE_EXTENSION_FUNCTION("i18n.detectLanguage", I18N_DETECTLANGUAGE)
+};
+
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_I18N_I18N_API_H_