Don't crash when logging if CommandLine is uninitialized.

The base::CommandLine singleton is usually initialized from
main(), but some gtest-based unit tests don't have control
over that function. Guard CommandLine accesses in
base/logging.cc to handle this gracefully.

Bug: 24536569
Change-Id: If3eab0f36c28bb6b3cf3569c61c7d7cec5cf7b10
1 file changed