Remove unneeded AddRef in RenderViewTest::SetUp

The AddRef in RenderViewTest::SetUp is not needed and can lead to leaks
in tests. RenderView takes a reference on itself during initialization
and drops it in RenderWidget::Close (which it inherits & calls directly).

TBR=jam@chromium.org
BUG=357747

Review URL: https://codereview.chromium.org/1135643002

Cr-Commit-Position: refs/heads/master@{#328991}
1 file changed