Merge to XFA: Fix leaks in the embedder tests themselves.

Also change EmbedderTest::TearDown() to match the destruction order in
Chromium's PDF code.

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1138143003

(cherry picked from commit 61ffad8df484ab9b3f7d2f5519ec470fbc023b88)

Review URL: https://codereview.chromium.org/1138973004
5 files changed