[GCM] Move extension specific tests out of gcm_profile_service_unit_test

These tests are moved to extension_gcm_profile_service_unittest.
Also did some cleanup.

BUG=356421
TEST=tests updated and new tests added

Review URL: https://codereview.chromium.org/213313006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@261568 0039d316-1c4b-4281-b951-d872f2087c98
9 files changed