Files.app: Fix a moving progressing message from Downloads to Drive.

To move a file between different volumes, FileOperationManager uses CopyTask and
removes the original files after copying. This caused to a bug that the message
of the copy task is assigned to the move operations.

This CL adds a deleteAfterCopy flag to the constructor of CopyTask and
determines the message by referring the flag.

Along the way, this CL removes lines that is not used in FileOperationManager.

BUG=336335
TEST=manually

Review URL: https://codereview.chromium.org/143343004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246293 0039d316-1c4b-4281-b951-d872f2087c98
Remove FILE_MANAGER_EXTENSION and related configuration. They can be folded back to Chrome OS as condition.

BUG=166934

Review URL: https://codereview.chromium.org/143733002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246294 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246294
Quota: Run didGrantStorageQuota with usage and granted_quota

Depends on blink-side change (https://codereview.chromium.org/143913002/)


BUG=332325
TEST=should pass all existing tests (no behavioral change)
TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/143923002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246295 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246295