Adding instrumentation points for tracing of I/O calls

[Staffan Larsen]

I have recently started a review thread [1] on the core-libs-dev alias about a change to add instrumentation for I/O calls. This change was targeted at both 7u12 and 8. The consensus in that thread is that the changes look good, but should ideally be replaced by dynamic bytecode instrumentation. Because of the short time remaining for 7u12, I will not have time to redo the implementation for this release. Thus the suggested plan was to make the proposed change in 7u12 and do dynamic bytecode instrumentation for 8.

So, this is seeking approval for integrating the changes [2] in the original thread into 7u-dev. 

Thanks,
/Staffan


[1] http://mail.openjdk.java.net/pipermail/core-libs-dev/2012-November/012217.html
[2] http://cr.openjdk.java.net/~sla/8003322/webrev.01/