Remove base::OnceCallback<void()> from disallow_list.

It was added to the whitelist in https://crrev.com/c/807754.

Bug: 771087,763980
Change-Id: I3f168415bba5cfcf4383c30c3ef6e66036ffc050
Reviewed-on: https://chromium-review.googlesource.com/892195Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Yuta Kitamura <yutak@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Fergal Daly <fergal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532768}

third_party/WebKit/PRESUBMIT_test.py

@@ -121,7 +121,6 @@ class CxxDependencyTest(unittest.TestCase):
     disallow_list = [
         'GURL',
         'base::Callback<void()>',
-        'base::OnceCallback<void()>',
         'content::RenderFrame',
         'gfx::Point',
         'gfx::Rect',