DevTools: [HeapProfiler] Provide API for heap objects tracking info.

We can track changes in the v8 heap. With these data we will be able
to map a time range to the heap object ids range. As a result we could draw
a time range selector for heap snapshot and event support a live view
for v8 heap changes.

BUG=none
TEST=none
R= pfeldman@chromium.org, yurys@chromium.org

Review URL: https://codereview.chromium.org/14373016

git-svn-id: svn://svn.chromium.org/blink/trunk@149106 bbb929c8-8fbe-4397-9dbb-9b2b20218538
10 files changed