Replace signin dialog with browser tab.
This should resolve unexpected behaivour user click links of sign in window.

BUG=332294

Review URL: https://codereview.chromium.org/131193009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244721 0039d316-1c4b-4281-b951-d872f2087c98
video: Make the Webrtc content browser tests produce pixel output.

These tests require pixel output to make progress. Currently they are
being run in an unsupported legacy software mode, which is able to
produce pixels even though the browser compositor does not draw
anything. Once the renderer is put in compositing mode, then pixel
output becomes required.

This change makes the tests produce pixel output in both the ui and
(future) renderer compositor.

A number of tests in this suite are long tests that test multiple
configurations. These tests are quite slow, so split them up into
smaller tests.

Depends on: https://codereview.chromium.org/132503002/

R=fischman@chromium.org
BUG=270918,333406

Review URL: https://codereview.chromium.org/131663004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244722 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244722