Refactor EncryptedMediaTest.

- Use GetParam() to get rid of a lot of special cases and duplicate code.
- Use kDisableGestureRequirementForMediaPlayback for encrypted media test on Android. Without this flag the tests will timeout.

BUG=300035
TEST=Tests doesn't time out now. They still fail and I'll keep investigating.

Review URL: https://codereview.chromium.org/25749004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227472 0039d316-1c4b-4281-b951-d872f2087c98
Enable batched browser shutdown by default.

BUG=265764

Review URL: https://codereview.chromium.org/25842005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227473 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227472
SVN changes up to revision 227473