Revert of cc: Remove the --enable-partial-swap flag. (https://codereview.chromium.org/167953003/)

Reason for revert:
Should have only enabled this on ChromeOS. Enabled elsewhere by mistake.

Original issue's description:
> cc: Remove the --enable-partial-swap flag.
> 
> R=piman
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=251898

TBR=piman@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/172763002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252038 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252038