Change how the AppDetailsDelegate is used

Move the async task and callback into the implementation class directly
so that it can do whatever it needs to do when the request arrives.

BUG=341556

Review URL: https://codereview.chromium.org/189163010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256428 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256428
[Android] Lint the rest of pylib.

BUG=168518

Review URL: https://codereview.chromium.org/194843003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256429 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256429