One thing I personally hate is when people claim someone is defimitely chucking. Fair enough, he clearly has an odd looking action but there is no way anybody can say for certain he is chucking. I'm not saying he's not, and its good that he's going to be tested, but accusing someone of 'cheating' without proof and no access to it is a big claim in my opinion.
"Chucking" is the act of straightening one's arm visibly in the delivery of the ball.
"Chucking legally" is the act of straightening one's arm by less than 15 degrees.
"Chucking illegally" is the act of straightening one's arm by more than 15 degrees.
The video footage of various deliveries from Ajmal, Narine, Senanayake and others clearly shows them straightening their arm. It is merely the degree of straightening that is in question. As long as you can see arm straightening going on then the ball is being thrown and not bowled.
It is simply a matter of semantics as to whether that is a "legal" throw or an "illegal" one...