Adjust RTL formatting for web notifications in cros system tray.

ash/common/system/web_notification/web_notification_tray.cc

Index: ash/common/system/web_notification/web_notification_tray.cc
diff --git a/ash/common/system/web_notification/web_notification_tray.cc b/ash/common/system/web_notification/web_notification_tray.cc
index 6a2470d36284e35b68d9455f8eff36f17fdb1871..60a8604f18bdb8a6c20cc8aa67d2d84ed49b2908 100644
--- a/ash/common/system/web_notification/web_notification_tray.cc
+++ b/ash/common/system/web_notification/web_notification_tray.cc
@@ -267,10 +267,9 @@ class WebNotificationLabel : public WebNotificationItem {
 
     base::string16 str = base::FormatNumber(notification_count);
     if (small_icons_exist) {
-      if (!base::i18n::IsRTL())
-        str = base::ASCIIToUTF16("+") + str;
-      else
-        str = str + base::ASCIIToUTF16("+");
+      str = base::ASCIIToUTF16("+") + str;
+      if (base::i18n::IsRTL())
+        base::i18n::WrapStringWithRTLFormatting(&str);

[mohsen, 2017/03/02 21:45:21]

If I understand correctly, when the context is RTL, we still want to show "+n"
text LTR (as mathematical expressions are written LTR in RTL languages). In this
case, shouldn't we use WrapStringWithLTRFormatting (note the LTR) to force "+n"
written LTR?

[Evan Stade, 2017/03/02 22:22:52]

We want to show "99+" in RTL. That is what Chrome currently does, this just
effects that more gracefully. You can go type plus nine nine in a hebrew web
page and see that on screen it looks like 99+.

This text is put in a label. Labels intuit their directionality from the text,
not the UI (i.e. they don't care about i18n::IsRTL()). "+99" on its own has no
strong directional characters. Thus we'd fall back to a default of LTR for
displaying it. Wrapping with the RTL indicating character simply makes us use
RTL to display "+99", which ends up looking like "99+" on screen.

The only thing effectively incorrect about the present code is what the output
of a screen reader would be.

[mohsen, 2017/03/03 04:25:35]

I see. I agree that your change is a better way of implementing the current
behavior. However, that behavior seems wrong to me. At least in Persian (and I
believe in other RTL languages) "99+" and "+99" (with Persian digits) mean the
same as in English. But, I also realize that this design for notification tray,
which works perfectly in LTR (e.g. "😁 +3" means a notification (😁) plus three
more), does not work well for RTL languages (none of "+3 😁" and "3+ 😁" seem
good, though I prefer the former). Anyways, I'll file a bug about this and see
what people think.

     }
 
     view_->SetText(str);