Add a Resource Mutate Visitor to enforce that a resource is in cache

Added a cache aware resource mutate visitor that reserves html tag nodes whose uri attributes are either not in cache, or are in cache, but the response in cache is either stale or an error response. This is so that any later visitors do not use these nodes.

[nikhilmadan23, 2011-01-06 11:10:39]

Removing Useless Test

[anupama.dutta, 2011-01-07 04:16:05]

LGTM. Please send out on dev@.

[gagan.goku, 2011-01-07 08:33:35]

lgtm

http://codereview.appspot.com/3780045/diff/6001/java/gadgets/src/main/java/or...
File
java/gadgets/src/main/java/org/apache/shindig/gadgets/rewrite/CacheEnforcementVisitor.java
(right):

http://codereview.appspot.com/3780045/diff/6001/java/gadgets/src/main/java/or...
java/gadgets/src/main/java/org/apache/shindig/gadgets/rewrite/CacheEnforcementVisitor.java:49:

remove extra newline

[nikhilmadan23, 2011-01-07 08:43:28]

http://codereview.appspot.com/3780045/diff/6001/java/gadgets/src/main/java/or...
File
java/gadgets/src/main/java/org/apache/shindig/gadgets/rewrite/CacheEnforcementVisitor.java
(right):

http://codereview.appspot.com/3780045/diff/6001/java/gadgets/src/main/java/or...
java/gadgets/src/main/java/org/apache/shindig/gadgets/rewrite/CacheEnforcementVisitor.java:49:

On 2011/01/07 08:33:35, gagan.goku wrote:
> remove extra newline

Done.

[satya3656, 2011-01-10 12:14:24]

How about making the prefetching optional, controlled by constructor parameter?

[gagan.goku, 2011-01-19 11:16:54]

On 2011/01/10 12:14:24, satya3656 wrote:
> How about making the prefetching optional, controlled by constructor
parameter?

Build looks good.
Committed as r1060766.