Implemented new Translate API for purely Objective-C clients.

ios/web_view/shell/shell_translation_delegate.m

Index: ios/web_view/shell/shell_translation_delegate.m
diff --git a/ios/web_view/shell/shell_translation_delegate.m b/ios/web_view/shell/shell_translation_delegate.m
new file mode 100644
index 0000000000000000000000000000000000000000..32c8087b18c202450d0d0a6ede95e5843ec4547c
--- /dev/null
+++ b/ios/web_view/shell/shell_translation_delegate.m
@@ -0,0 +1,73 @@
+// 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.
+
+#import "ios/web_view/shell/shell_translation_delegate.h"
+
+#import <ChromeWebView/ChromeWebView.h>

[michaeldo, 2017/05/01 18:25:38]

Can we remove ChromeWebView import, it is already imported in header?

[jzw1, 2017/05/08 03:36:28]

Done.

+#import <UIKit/UIKit.h>
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@interface ShellTranslationDelegate ()
+// Action Sheet to prompt user whether or not the page should be translated.
+@property(nonatomic, strong) UIAlertController* beforeTranslateActionSheet;
+@end
+
+@implementation ShellTranslationDelegate
+
+@synthesize beforeTranslateActionSheet = _beforeTranslateActionSheet;
+
+- (void)dealloc {
+  [_beforeTranslateActionSheet dismissViewControllerAnimated:YES
+                                                  completion:nil];
+}
+
+#pragma mark - CWVTranslationDelegate methods
+
+- (void)translationController:(CWVTranslationController*)controller
+    didFinishLanguageDetectionWithResult:(CWVLanguageDetectionResult*)result
+                                   error:(NSError*)error {
+  self.beforeTranslateActionSheet = [UIAlertController
+      alertControllerWithTitle:nil
+                       message:@"Translate?"
+                preferredStyle:UIAlertControllerStyleActionSheet];
+  UIAlertAction* cancelAction =
+      [UIAlertAction actionWithTitle:@"Nope."
+                               style:UIAlertActionStyleCancel
+                             handler:^(UIAlertAction* action) {
+                               self.beforeTranslateActionSheet = nil;

[michaeldo, 2017/05/01 18:25:38]

Please use __weak self reference inside action handler because self holds strong
reference to this alert.

[jzw1, 2017/05/08 03:36:29]

Done.

+                             }];
+  [_beforeTranslateActionSheet addAction:cancelAction];
+
+  UIAlertAction* translateAction = [UIAlertAction
+      actionWithTitle:@"Yes!"
+                style:UIAlertActionStyleDefault
+              handler:^(UIAlertAction* action) {
+                self.beforeTranslateActionSheet = nil;

[michaeldo, 2017/05/01 18:25:38]

Please use __weak self reference inside action handler because self holds strong
reference to this alert.

[jzw1, 2017/05/08 03:36:28]

Done.

+                CWVTranslationLanguage* source = result.pageLanguage;
+                CWVTranslationLanguage* target = result.suggestedTargetLanguage;
+                [controller translatePageFromLanguage:source toLanguage:target];
+              }];
+  [_beforeTranslateActionSheet addAction:translateAction];
+
+  [[UIApplication sharedApplication].keyWindow.rootViewController
+      presentViewController:_beforeTranslateActionSheet
+                   animated:YES
+                 completion:nil];
+}
+
+- (void)translationController:(CWVTranslationController*)controller

[michaeldo, 2017/05/01 18:25:38]

No need for empty implementations because these delegate methods are optional.

[jzw1, 2017/05/08 03:36:28]

Done.

+    didStartTranslationFromLanguage:(CWVTranslationLanguage*)sourceLanguage
+                         toLanguage:(CWVTranslationLanguage*)targetLanguage {
+}
+
+- (void)translationController:(CWVTranslationController*)controller
+    didFinishTranslationFromLanguage:(CWVTranslationLanguage*)sourceLanguage
+                          toLanguage:(CWVTranslationLanguage*)targetLanguage
+                               error:(NSError*)error {
+}
+
+@end