Oilpan: Move CallbackStack to its own file.

This change moves the "invoke" part of the templated
popAndInvokeCallback to the call sites. The ephemeron processing in
invokeCallbacks is renamed to invokeEphemeronCallbacks to signify that
it is specially crafted for processing the ephemeron stack.

R=ager@chromium.org, haraken@chromium.org
BUG=

Review URL: https://codereview.chromium.org/595783002

git-svn-id: svn://svn.chromium.org/blink/trunk@182481 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Minor compile_frontend.py cleanup

TBR=aandrey
NOTRY=true

Review URL: https://codereview.chromium.org/589403003

git-svn-id: svn://svn.chromium.org/blink/trunk@182482 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Mark http/tests/media/gc-while-network-loading.html as slow

The test has slow runs of 3 seconds on Linux and Mac, and occasionally
times out at 6 seconds on Windows.

A more sophisticated server-side script could serve the first half of
the file very quickly and then trickle the rest.

BUG=400659
NOTRY=true
R=fs@opera.com

Review URL: https://codereview.chromium.org/591313003

git-svn-id: svn://svn.chromium.org/blink/trunk@182483 bbb929c8-8fbe-4397-9dbb-9b2b20218538