The Chrome DevTools protocol part of the XDK

in-depth allocation tracker

There are three new commands are added by analogy with Chrome DevTools
allocation tracker. Start/Stop and Event which is sent by timer.
Command stopTrackingHeapXDK accepts three parameters: stack depth for unwinding,
Sample After Value - period of timer and a flag to collect retention
information or not. Event sends to the host currently collected data about
symbols/callstack/objects. Command stopTrackingHeapXDK returns the final
info witch is similar to Event passed format with one more parameter: duration
of the collection.

Basing on this info consumer can build allocation call tree for any period of
time, annotate source by self and total allocation mertics and annotate
allocation call tree by the objects, which retain other objects in the memory
Merge pull request #29 from elvin-nnov/master

The Chrome DevTools protocol part of the XDK