Revert of Implement '--gpu-sandbox-failures-nonfatal' flag. (https://codereview.chromium.org/189313002/)

Reason for revert:
Looks like this broke Linux ChromiumOS Tests (2):
http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%282%29/builds/22114

Original issue's description:
> Implement '--gpu-sandbox-failures-nonfatal' flag.
> 
> Also, move the flag to content:: instead of chromeos::.
> 
> BUG=327824
> TEST=Chrome compiles, loads with and without the flag.
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=255564

TBR=jln@chromium.org,piman@chromium.org,jorgelo@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=327824

Review URL: https://codereview.chromium.org/189093008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255578 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255578