GitLab

Use ExtensionRegistry instead from file_system, location, management apis.
and Use content:BrowserContext instead of Profile.
and Remove unwanted extensions:: namespace prefix from management api.

TEST=browser_tests --gtest_filter=FileSystemApiTest.*
R=rdevlin.cronin@chromium.org
BUG=354046

Review URL: https://codereview.chromium.org/330383003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278486 0039d316-1c4b-4281-b951-d872f2087c98