Got chaining working with composite valve. Now we have a proper valve chain as follows:
 
 TomcatValve chain -> CarbonTomcatValve chain ->  TomcatValve chain

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/kernel/trunk@178036 a5903396-d722-0410-b921-86c7d4935375