Revert 225917 "Media Galleries: Run API tests in a temp director..."

> Media Galleries: Run API tests in a temp directory with an injected common.js file. Avoid the need for nested tests to share common JS code.
> 
> Review URL: https://codereview.chromium.org/24420003

TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/25222002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225927 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225927