Remove TileItemBackground from experimental app list.

Remove TileItemBackground from experimental app list.

This CL removes the white TileItemBackground from the tiles on the
experimental app list start page.

BUG=349727
Committed: https://crrev.com/3cd167db1ebbbe61fc62405fd70763e35cd9efda
Cr-Commit-Position: refs/heads/master@{#291632}

[calamity, 2014-08-21 03:56:37]

Pour one out for the tile item background.

[Matt Giuca, 2014-08-21 06:48:05]

Well this is awfully disappointing :(((((((((((((((((

lgtm

[calamity, 2014-08-22 02:39:58]

The CQ bit was checked by calamity@chromium.org

[commit-bot: I haz the power, 2014-08-22 02:40:54]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/calamity@chromium.org/492153002/60001

[commit-bot: I haz the power, 2014-08-22 05:44:35]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_chromium_gn_compile_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)
  android_dbg_tests_recipe on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_dbg_tes...)
  linux_chromium_rel_swarming on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[commit-bot: I haz the power, 2014-08-22 05:47:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-08-22 05:47:43]

Try jobs failed on following builders:
  android_chromium_gn_compile_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)

[calamity, 2014-08-25 00:37:45]

The CQ bit was checked by calamity@chromium.org

[commit-bot: I haz the power, 2014-08-25 00:38:11]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/calamity@chromium.org/492153002/60001

[commit-bot: I haz the power, 2014-08-25 01:33:28]

Committed patchset #2 (60001) as 6e96c28a2a59fac44695f03ede293ad3629caa5d

[commit-bot: I haz the power, 2014-09-10 02:32:50]

Patchset 2 (id:??) landed as
https://crrev.com/3cd167db1ebbbe61fc62405fd70763e35cd9efda
Cr-Commit-Position: refs/heads/master@{#291632}