Set input and textarea font size to 16px on iOS (#7480)

lib/mobile_detection.rb

@@ -16,4 +16,9 @@ module MobileDetection
       mobile_device?(user_agent)
     end
   end
+
+  def self.ios_device?(user_agent)
+    user_agent =~ /iPad|iPhone|iPod/
+  end
+
 end