Fix mojo and mandoline android build breaks.

Fix mojo and mandoline android build breaks.

Exclude the mandoline target on android for now (no main).
Rename the test targets to avoid naming conflicts...
(android GN targets doesn't seem to respect output_name)
Update the namespace for mojo::util::FilePathToFileURL call.

See initial breakage at http://build.chromium.org/p/chromium.mojo/builders/Chromium%20Mojo%20Android/builds/384

The relevant CLs are:
  https://codereview.chromium.org/1109993002
  https://codereview.chromium.org/1091513005

BUG=466129
TEST=Building mojo and mandoline for android passes.
R=sky@chromium.org,ben@chromium.org

Committed: https://crrev.com/887c30157baaa9242a798ba8a5a4884d9564b11f
Cr-Commit-Position: refs/heads/master@{#327361}

[msw, 2015-04-28 19:41:04]

msw@chromium.org changed reviewers:
+ ben@chromium.org

[msw, 2015-04-28 19:41:36]

Hey Scott and Ben, please take a look; thanks!
(I'd like to get android to support output_name...)

[sky, 2015-04-28 19:45:19]

LGTM

[msw, 2015-04-28 19:51:20]

The CQ bit was checked by msw@chromium.org

[commit-bot: I haz the power, 2015-04-28 19:51:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1115463002/20001

[commit-bot: I haz the power, 2015-04-28 20:53:29]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-28 20:54:16]

Patchset 2 (id:??) landed as
https://crrev.com/887c30157baaa9242a798ba8a5a4884d9564b11f
Cr-Commit-Position: refs/heads/master@{#327361}