Exclude unused strings for chrome://ntp on Android

Relanding https://codereview.chromium.org/174453002 as it got reverted in https://codereview.chromium.org/177903009

BUG=326023
TBR=estade

Review URL: https://codereview.chromium.org/183793008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256507 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256507
Remove command line switches for accelerated compositing/scrolling frames

This doesn't change the default behavior of any platform. On platforms other
than Android, this change makes the accelerated compositing/scrolling frames
feature automatically enabled if --kForceCompositingMode is specified on high
DPI devices.

BUG=304900

Review URL: https://codereview.chromium.org/181883002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256508 0039d316-1c4b-4281-b951-d872f2087c98
MSE: Lift timestampOffset and appendWindow[Start,End] storage to WebSourceBufferImpl

Lifts timestamp offset and append window variables out of SourceState in
preparation for the upcoming refactoring of coded frame processing out
of SourceState.

R=acolwell@chromium.org
BUG=249422
TEST=All media_unittests and http/tests/media layout tests pass locally on Linux

Review URL: https://codereview.chromium.org/196173002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256509 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256509