Indicate focused state on text buttons with blue outline.

ui/base/native_theme/native_theme.h

Index: ui/base/native_theme/native_theme.h
diff --git a/ui/base/native_theme/native_theme.h b/ui/base/native_theme/native_theme.h
index b37b1e7cef895a0c82bafac931762966f8a30396..0c9ebcd7f03a619ce18257ca7f225776ae84c405 100644
--- a/ui/base/native_theme/native_theme.h
+++ b/ui/base/native_theme/native_theme.h
@@ -94,6 +94,7 @@ class UI_EXPORT NativeTheme {
     bool indeterminate;  // Whether the button state is indeterminate.
     bool is_default;  // Whether the button is default button.
     bool has_border;
+    bool is_focused;
     int classic_state;  // Used on Windows when uxtheme is not available.
     SkColor background_color;
   };