Renable PosixDynamicThreadPoolTest.Basic on TSAN v2.

The test is reenabled, and a check which introduced a real race condition
has been removed. The check is unnecessary.

BUG=305100

Review URL: https://codereview.chromium.org/26631003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229101 0039d316-1c4b-4281-b951-d872f2087c98
drive: reduce the max entries to fetch in full feed per request from 500 to 250.

BUG=297404

Review URL: https://codereview.chromium.org/26707005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229102 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229102