Two techniques are involved:
 - compress repeated line ends (common stack beginnings) by using back references;
 - do RLE compression of repeated tick events.

This gives only 5% size reduction on benchmarks run, but this is because tick events are only comprise 10% of file size. Under Chromium winnings are bigger because long repeated samples of idleness are now compressed into a single line.

Tickprocessor will be updated in the next patch.

Review URL: http://codereview.chromium.org/123012


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2147 ce2b1a6d-e550-0410-aec6-3dcde31c8c00