Add JavaScript prompts support to CWVUIDelegate.

ios/web_view/shell/shell_view_controller.m

Index: ios/web_view/shell/shell_view_controller.m
diff --git a/ios/web_view/shell/shell_view_controller.m b/ios/web_view/shell/shell_view_controller.m
index 152279a665cf3fef3ca79ed4120b9b80b5098e49..f1c15934ea0540a9142ab4be8d5ff2f0d8a93a37 100644
--- a/ios/web_view/shell/shell_view_controller.m
+++ b/ios/web_view/shell/shell_view_controller.m
@@ -15,6 +15,10 @@
 #error "This file requires ARC support."
 #endif
 
+// Externed accessibility identifier.
+NSString* const kWebViewShellJavaScriptDialogTextFieldAccessibiltyIdentifier =
+    @"WebViewShellJavaScriptDialogTextFieldAccessibiltyIdentifier";
+
 @interface ShellViewController ()
 // Container for |webView|.
 @property(nonatomic, strong) UIView* containerView;
@@ -214,6 +218,87 @@
   [self presentViewController:alert animated:YES completion:nil];
 }
 
+- (void)webView:(CWVWebView*)webView
+    runJavaScriptAlertPanelWithMessage:(NSString*)message
+                               pageURL:(NSURL*)URL
+                     completionHandler:(void (^)(void))handler {
+  UIAlertController* alert =
+      [UIAlertController alertControllerWithTitle:nil
+                                          message:message
+                                   preferredStyle:UIAlertControllerStyleAlert];
+
+  [alert addAction:[UIAlertAction
+                       actionWithTitle:@"Ok"
+                                 style:UIAlertActionStyleDefault
+                               handler:^(UIAlertAction* _Nonnull action) {

[Eugene But (OOO till 7-30), 2017/02/27 18:30:53]

Is it possible to remove |action| to improve the formatting?

[michaeldo, 2017/02/27 21:35:51]

I get an error without the parameter name, but I can remove the nullability
annotations which cleans up the formatting a bit.

+                                 handler();
+                               }]];
+
+  [self presentViewController:alert animated:YES completion:nil];
+}
+
+- (void)webView:(CWVWebView*)webView
+    runJavaScriptConfirmPanelWithMessage:(NSString*)message
+                                 pageURL:(NSURL*)URL
+                       completionHandler:(void (^)(BOOL))handler {
+  UIAlertController* alert =
+      [UIAlertController alertControllerWithTitle:nil
+                                          message:message
+                                   preferredStyle:UIAlertControllerStyleAlert];
+
+  [alert addAction:[UIAlertAction
+                       actionWithTitle:@"Ok"
+                                 style:UIAlertActionStyleDefault
+                               handler:^(UIAlertAction* _Nonnull action) {
+                                 handler(true);

[Eugene But (OOO till 7-30), 2017/02/27 18:30:52]

s/true/YES

[michaeldo, 2017/02/27 21:35:51]

Done.

+                               }]];
+  [alert addAction:[UIAlertAction
+                       actionWithTitle:@"Cancel"
+                                 style:UIAlertActionStyleCancel
+                               handler:^(UIAlertAction* _Nonnull action) {
+                                 handler(false);

[Eugene But (OOO till 7-30), 2017/02/27 18:30:53]

s/false/NO

[michaeldo, 2017/02/27 21:35:51]

Done.

+                               }]];
+
+  [self presentViewController:alert animated:YES completion:nil];
+}
+
+- (void)webView:(CWVWebView*)webView
+    runJavaScriptTextInputPanelWithPrompt:(NSString*)prompt
+                              defaultText:(NSString*)defaultText
+                                  pageURL:(NSURL*)URL
+                        completionHandler:(void (^)(NSString*))handler {
+  UIAlertController* alert =
+      [UIAlertController alertControllerWithTitle:nil
+                                          message:prompt
+                                   preferredStyle:UIAlertControllerStyleAlert];
+
+  [alert addTextFieldWithConfigurationHandler:^(UITextField* textField) {
+    textField.text = defaultText;
+    textField.accessibilityIdentifier =
+        kWebViewShellJavaScriptDialogTextFieldAccessibiltyIdentifier;
+  }];
+
+  __weak UIAlertController* weakAlert = alert;
+  [alert addAction:[UIAlertAction
+                       actionWithTitle:@"Ok"
+                                 style:UIAlertActionStyleDefault
+                               handler:^(UIAlertAction* _Nonnull action) {
+                                 NSString* textInput = nil;
+                                 if (weakAlert.textFields.count > 0) {
+                                   textInput = weakAlert.textFields[0].text;

[Eugene But (OOO till 7-30), 2017/02/27 18:30:53]

How about this?:

NSString* textInput = weakAlert.textFields.firstObject.text;
handler(textInput);

[michaeldo, 2017/02/27 21:35:51]

Done.

+                                 }
+                                 handler(textInput);
+                               }]];
+  [alert addAction:[UIAlertAction
+                       actionWithTitle:@"Cancel"
+                                 style:UIAlertActionStyleCancel
+                               handler:^(UIAlertAction* _Nonnull action) {
+                                 handler(nil);
+                               }]];
+
+  [self presentViewController:alert animated:YES completion:nil];
+}
+
 #pragma mark CWVWebViewDelegate methods
 
 - (void)webView:(CWVWebView*)webView