Extract creation of PWG Raster converter settings out of privet_http_impl

Extract creation of PWG Raster converter settings out of privet_http_impl

Moves creation of conversion_settings and bitmap_settings needed by
PWGRasterConverter::Start to a place usable by code for handling
extension printers. This will enable extension printer handler to reuse
the code when converting pdf documents to PWG raster data.

BUG=408772
TEST=existing tests

Committed: https://crrev.com/885330e8a260d0f76a8f41536a0c011b21839d70
Cr-Commit-Position: refs/heads/master@{#316958}

[tbarzic, 2015-02-18 02:55:44]

tbarzic@chromium.org changed reviewers:
+ vitalybuka@chromium.org

[tbarzic, 2015-02-18 02:55:44]

Let me know if you know a better place to put these..

[Vitaly Buka (NO REVIEWS), 2015-02-18 23:43:33]

lgtm

[tbarzic, 2015-02-18 23:49:37]

The CQ bit was checked by tbarzic@chromium.org

[commit-bot: I haz the power, 2015-02-18 23:51:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/935673004/60001

[commit-bot: I haz the power, 2015-02-19 01:34:56]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-02-19 01:35:44]

Patchset 4 (id:??) landed as
https://crrev.com/885330e8a260d0f76a8f41536a0c011b21839d70
Cr-Commit-Position: refs/heads/master@{#316958}