Make LoadIconFromExtension check Chrome-OS-ness

The icon loading helper functions, prior to both this CL and
http://crrev.com/c/1373450, called app_list image processing functions
unconditionally, which broke the build, as app_list is Chrome OS only.

The quick fix was to build app_icon_factory.cc conditionally, only for
Chrome OS. This was http://crrev.com/c/1373450

This fix is to make more of app_icon_factory.cc conditional on #ifdef
OS_CHROMEOS. The App Service isn't necessarily Chrome OS only.

A longer term possibility is to move the app_list image processing
function out of //chrome/browser/ui/app_list per se, and build it
unconditionally. This would be a user-visible change (in that extension
icons on desktop Chrome might look different), but arguably a change
that improves consistency. In any case, doing that is out of scope of
this CL. In the initial stage, the App Service aims to be a
user-invisible refactoring.

BUG=826982

Change-Id: Ic4fd3db27789117bb57e72e6b557b3e56b28fb7f
Reviewed-on: https://chromium-review.googlesource.com/c/1374889
Commit-Queue: Nigel Tao <nigeltao@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616190}
2 files changed