Improve dialog titles generated by embedded pages.

ios/chrome/browser/ui/dialogs/dialog_presenter.mm

Index: ios/chrome/browser/ui/dialogs/dialog_presenter.mm
diff --git a/ios/chrome/browser/ui/dialogs/dialog_presenter.mm b/ios/chrome/browser/ui/dialogs/dialog_presenter.mm
index 1d7094f85022a5d80460a8bc6ed0ddd9b0abf825..2ea10d5afd4f93264abcdb95ebe973e8ca6afe67 100644
--- a/ios/chrome/browser/ui/dialogs/dialog_presenter.mm
+++ b/ios/chrome/browser/ui/dialogs/dialog_presenter.mm
@@ -31,12 +31,6 @@
 NSString* const kJavaScriptDialogTextFieldAccessibiltyIdentifier =
     @"JavaScriptDialogTextFieldAccessibiltyIdentifier";
 
-namespace {
-// The hostname to use for JavaScript alerts when there is no valid hostname in
-// the URL passed to |+localizedTitleForJavaScriptAlertFromPage:type:|.
-const char kAboutNullHostname[] = "about:null";
-}  // namespace
-
 @interface DialogPresenter () {
   // Queue of WebStates which correspond to the keys in
   // |_dialogCoordinatorsForWebStates|.
@@ -347,11 +341,16 @@ const char kAboutNullHostname[] = "about:null";
 }
 
 + (NSString*)localizedTitleForJavaScriptAlertFromPage:(const GURL&)pageURL {
+  NSString* localizedTitle = nil;
   NSString* hostname = base::SysUTF8ToNSString(pageURL.host());
-  if (!hostname.length)
-    hostname = base::SysUTF8ToNSString(kAboutNullHostname);
-  return l10n_util::GetNSStringF(IDS_JAVASCRIPT_MESSAGEBOX_TITLE,
-                                 base::SysNSStringToUTF16(hostname));
+  if (!hostname.length) {

[Eugene But (OOO till 7-30), 2017/06/22 20:19:12]

Other platforms use IDS_JAVASCRIPT_MESSAGEBOX_TITLE_NONSTANDARD_URL_IFRAME when
dialog is requested by iframe, not when hostname is empty. Can we follow the
same logic as other platforms?:

bool is_same_origin_as_main_frame =
      (web_contents->GetURL().GetOrigin() == origin_url.GetOrigin());

ios has web_state instead of web_contents, but everything else can be the same.

+    localizedTitle = l10n_util::GetNSString(
+        IDS_JAVASCRIPT_MESSAGEBOX_TITLE_NONSTANDARD_URL_IFRAME);
+  } else {
+    localizedTitle = l10n_util::GetNSStringF(
+        IDS_JAVASCRIPT_MESSAGEBOX_TITLE, base::SysNSStringToUTF16(hostname));
+  }
+  return localizedTitle;
 }
 
 #pragma mark - Private methods.