No need to call InitGoogleMock() ourselves.

base's TestSuite already does this for us, so we can just let it handle
that detail, instead of doing this twice.

BUG=None
TEST=webkit_unit_tests
R=abarth@chromium.org

Review URL: https://codereview.chromium.org/401733002

git-svn-id: svn://svn.chromium.org/blink/trunk@178416 bbb929c8-8fbe-4397-9dbb-9b2b20218538