Create a gfx/resources dir to hold gfx package resources.
- bitmap_brush_image.png used to be the only gfx resource for
  canvas_direct2d_unittest;
- Files prefixed with "linux-" are from webkit/glue/resources. They will
  be used by NativeThemeLinux as we move webkit RenderTheme parts
  drawing code into it. The original files will still live for a while
  after we finish the switch.

BUG=chromium-os:9256
TEST=none. No behavior change.

Review URL: http://codereview.chromium.org/6362002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@71455 0039d316-1c4b-4281-b951-d872f2087c98