Bug 61917

Overview:
I want to use AddDefaultCharsetFilter as a generic purpose filter not only for type text/* but also for type application/json, appliation/javascript, etc.

Steps to Reproduce:
1) Adding a filter registeration in web.xml
<filter>
	<filter-name>AddDefaultCharset</filter-name>
	<filter-class>org.apache.catalina.filters.AddDefaultCharsetFilter</filter-class>
	<init-param>
		<param-name>encoding</param-name>
		<param-value>UTF-8</param-value>
	</init-param>
</filter>
<filter-mapping>
	<filter-name>AddDefaultCharset</filter-name>
	<servlet-name>default</servlet-name>
</filter-mapping>

2. Requesting a static json(e.g. /test.json) resource

Actual Results:
No default charset added in response header 'Content-Type'.
(AddDefaultCharsetFilter only adds default charset for type 'text/*')

Expected Results:
Add default charset for specified types.
response types which will be processed by AddDefaultCharsetFilter can be specified through a init-param (e.g. with name 'accept' and with value 'application/json,text/*'),
if the init-param not present, use defaut value 'text/*'