Clean-up: Replaces gfx::Font with gfx::FontList in ui/app_list.

As a part of effort to support multiple fonts, this CL changes methods to take gfx::FontList instead of gfx::Font, and to use new methods.

See https://docs.google.com/a/chromium.org/document/d/1D_25fp9B8b9aZJORfAjDIFq61NWvUquZ5xmKH-VcC4k/view

BUG=265485
TEST=Run views_unittests, ui_unittests and unit_tests.

Review URL: https://codereview.chromium.org/119963002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242518 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242518
Remove UTF string conversion functions from the global namespace.

BUG=330556
TEST=no change
TBR=ben@chromium.org

Review URL: https://codereview.chromium.org/102993018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242519 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242519