DevTools: Fix class filter in heap allocation recording profile.

When a selection window is changing in heap allocations profile
the class filter effect gets reset so all the nodes falling into the
window is shown. That's now fixed.

R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/158323003

git-svn-id: svn://svn.chromium.org/blink/trunk@166925 bbb929c8-8fbe-4397-9dbb-9b2b20218538