[ios] Workaround error affecting 3rd party keyboards and omnibox.

ios/chrome/browser/ui/omnibox/omnibox_text_field_ios.mm

Index: ios/chrome/browser/ui/omnibox/omnibox_text_field_ios.mm
diff --git a/ios/chrome/browser/ui/omnibox/omnibox_text_field_ios.mm b/ios/chrome/browser/ui/omnibox/omnibox_text_field_ios.mm
index 2be9472a98248f10a6d12cbd4faf200506c6ab25..4210f0757101aa6132142080d7b48127e129d692 100644
--- a/ios/chrome/browser/ui/omnibox/omnibox_text_field_ios.mm
+++ b/ios/chrome/browser/ui/omnibox/omnibox_text_field_ios.mm
@@ -14,7 +14,9 @@
 #include "base/strings/sys_string_conversions.h"
 #include "components/grit/components_scaled_resources.h"
 #include "components/omnibox/browser/autocomplete_input.h"
+#include "ios/chrome/browser/application_context.h"
 #include "ios/chrome/browser/autocomplete/autocomplete_scheme_classifier_impl.h"
+#include "ios/chrome/browser/experimental_flags.h"
 #import "ios/chrome/browser/ui/animation_util.h"
 #include "ios/chrome/browser/ui/omnibox/omnibox_util.h"
 #import "ios/chrome/browser/ui/reversed_animation.h"
@@ -458,7 +460,15 @@ NSString* const kOmniboxFadeAnimationKey = @"OmniboxFadeAnimation";
     [self clearAutocompleteText];
   }
 
-  self.attributedText = fieldText;
+  BOOL updateText = YES;
+  if (experimental_flags::IsThirdPartyKeyboardWorkaroundEnabled() &&
+      GetApplicationContext()->GetApplicationLocale() == "ja") {

[rohitrao (ping after 24h), 2017/06/27 13:48:47]

This should check the primaryLanguage of the current input, not the application
locale.

+    updateText =
+        (!self.editing || ![self.text isEqualToString:fieldText.string]);

[rohitrao (ping after 24h), 2017/06/27 13:48:47]

I think I'm ok with this, for two reasons:
1) We set a number of attributes in the omnibox, but the only ones that vary are
the foreground and background colors.  Other attributes (like font, style, etc)
are set for the entire string, and a few (strikethrough) are only set when not
editing.
2) setAttributedText always forces the color of the string when editing, so any
color attributes here would be ignored anyways.

Can you capture the gist of what I wrote above in a comment somewhere?

+  }
+  if (updateText) {
+    self.attributedText = fieldText;
+  }
 
   // iOS changes the font to .LastResort when some unexpected unicode strings
   // are used (e.g. 𝗲𝗺𝗽𝗵𝗮𝘀𝗶𝘀).  Setting the NSFontAttributeName in the