When drawing multiple box shadows, only use one save-clip-restore set, since the clip is the same for all shadows of a box model object.
When drawing multiple box shadows, only use one save-clip-restore
set, since the clip is the same for all shadows of a box model object.

BUG=244419

Review URL: https://chromiumcodereview.appspot.com/16046004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@151971 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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