Always set the transform matrix for layer transforms on the GraphicsContext, even with Slimming Paint on.
Always set the transform matrix for layer transforms on the GraphicsContext, even with Slimming Paint on.

This fixes an issue in which we were not properly tracking the current transform matrix, which
led to failures to antialias rotated borders.

Review URL: https://codereview.chromium.org/751143002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@185962 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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