base: Use nullptr instead of NULL and static_cast in discardable memory unit tests.

BUG=422953
TEST=base_unittests --gtest_filter=DiscardableMemoryTests*
TBR=danakj@chromium.org

Review URL: https://codereview.chromium.org/659143002

Cr-Commit-Position: refs/heads/master@{#299991}


CrOS-Libchrome-Original-Commit: d8ee1714ece7a563f981813381610fd37c37444e
1 file changed
tree: 67e6f889fe919a45b99e8bbe0a2653c8493e8128
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/