[GCM] Remove the requirement for manifest key

We also remove cert from the registration request.

BUG=345413
TEST=tests updated
R=fgorski@chromium.org, tim@chromium.org, zea@chromium.org

Review URL: https://codereview.chromium.org/179043005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255136 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255136
don't create SkDevice directly, use SkBitmap or (better) SkCanvas::NewRaster factory

BUG=skia:2239
TBR=scherkus@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=254567

reopened (after revewer) to address media_unittest valgrind issue

Review URL: https://codereview.chromium.org/184743002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255137 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255137