Remove athena targets from chromeos build

BUG=448472

Review URL: https://codereview.chromium.org/846293002

Cr-Original-Commit-Position: refs/heads/master@{#311557}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: c832e28f6b0fb78d0d62324aaa4e0098dd79dd6b

all.gyp

@@ -277,11 +277,6 @@
             '../extensions/shell/app_shell.gyp:*',
           ],
         }],
-        ['chromeos==1', {
-          'dependencies': [
-            '../athena/main/athena_main.gyp:*',
-          ],
-        }],
         ['envoy==1', {
           'dependencies': [
             '../envoy/envoy.gyp:*',
@@ -1337,7 +1332,6 @@
             }],
             ['chromeos==1', {
               'dependencies': [
-                '../athena/main/athena_main.gyp:*',
                 '../chromeos/chromeos.gyp:chromeos_unittests',
                 '../ui/chromeos/ui_chromeos.gyp:ui_chromeos_unittests',
               ],