Implemented new Translate API for purely Objective-C clients.

ios/web_view/public/cwv_language_detection_result.h

+// 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.
+
+#ifndef IOS_WEB_VIEW_PUBLIC_CWV_LANGUAGE_DETECTION_RESULT_H
+#define IOS_WEB_VIEW_PUBLIC_CWV_LANGUAGE_DETECTION_RESULT_H
+
+#import <ChromeWebView/cwv_export.h>
+#import <Foundation/Foundation.h>
+

[Eugene But (OOO till 7-30), 2017/04/26 20:15:30]

Do you want to use nullability macro here?

[jzw1, 2017/04/27 04:54:01]

Done.

+@class CWVTranslationLanguage;
+
+// Encapsulates the results of language detection in one class.
+CWV_EXPORT
+@interface CWVLanguageDetectionResult : NSObject
+
+- (instancetype)initWithSourceLanguage:(CWVTranslationLanguage*)sourceLanguage

[Eugene But (OOO till 7-30), 2017/04/26 20:15:30]

Does this method needs to be public? Client don't need to call it, right?

[jzw1, 2017/04/27 04:54:01]

moved to internal header file.

+                        targetLanguage:(CWVTranslationLanguage*)targetLanguage
+                    supportedLanguages:
+                        (NSArray<CWVTranslationLanguage*>*)supportedLanguages
+    NS_DESIGNATED_INITIALIZER;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+// The detected page language.
+@property(nonatomic, readonly) CWVTranslationLanguage* sourceLanguage;
+// The assumed target language based on OS locale.

[Eugene But (OOO till 7-30), 2017/04/26 20:15:30]

Do you want to be more specific (f.e. say that this is the language that the
page will be translated to.)

[jzw1, 2017/04/27 04:54:01]

Done.

+@property(nonatomic, readonly) CWVTranslationLanguage* targetLanguage;

[Eugene But (OOO till 7-30), 2017/04/26 20:15:30]

Should this be something like, suggestedTranslationLanguage? target language is
ambiguous. 

[Hiroshi Ichikawa, 2017/04/27 02:41:54]

I believe suggestedTranslationLanguage is also ambiguous, not clear whether it's
a language to translate from or translate into. Not really sure what is the good
name for it, but some ideas:

suggestedTargetLanguage
suggestedTranslationTargetLanguage
estimatedUserLanguage

[jzw1, 2017/04/27 04:54:01]

I will rename sourceLanguage to pageLanguage and targetLanguage to OSLanguage. 

[Eugene But (OOO till 7-30), 2017/04/27 13:08:08]

is targetLanguage always the same as OS language? If so, do we want to have it
in our API (i.e. iOS SDK has API for getting OS language)? If no, then we should
probably use different terminology than OSLanguage
(|suggestedTranslationTargetLanguage| sounds like a good name to me).

[jzw1, 2017/04/28 02:34:53]

Internally it returns the first non empty lang in the following order:
1. Override UI Language. (probably just debug?)
2. ULP Language?
3. Browser UI langauge. (OS Language)
4. First language in all accepted languages.
5. Nothing at all.

So as of right now, it'll only be the OS Language, unless we expose some ways to
provide #1 or #2. I feel that providing the OS Language is just a convenience
for the client so they don't have to create their own CWVTranslationLanguage
object. wdyt?

[Eugene But (OOO till 7-30), 2017/04/28 03:07:28]

So looks like the fact that result will be OS language is just an implementation
detail, which may change in the future. With that do you think we should use
OSLanguage as a name? 

[jzw1, 2017/04/28 05:43:35]

renamed to suggestedTranslationLanguage and updated comments.

[Hiroshi Ichikawa, 2017/04/28 05:50:06]

As I told in earlier comment, I feel suggestedTranslationLanguage is still a bit
ambiguous, and prefer suggestedTranslationTargetLanguage. But it's up to you.

+// The list of languages that can be used in translation.

[Eugene But (OOO till 7-30), 2017/04/26 20:15:30]

nit: "The list of supported languages that can be used in translation" ?

[jzw1, 2017/04/27 04:54:01]

Done.

+@property(nonatomic, readonly)
+    NSArray<CWVTranslationLanguage*>* supportedLanguages;
+
+@end
+
+#endif  // IOS_WEB_VIEW_PUBLIC_CWV_LANGUAGE_DETECTION_RESULT_H