Run chromium_trybot based Cast bots at 10%.

testing/commit_queue/config.json

 {
     "commit_burst_delay": 60,
     "commit_user": "commit-bot@chromium.org",
     "committer_project": "chromium",
     "cq_status_url": "https://chromium-cq-status.appspot.com",
     "git_repo_url": "https://chromium.googlesource.com/chromium/src",
     "hide_ref_in_committed_msg": true,
     "max_commit_burst": 2,
     "project_bases_legacy": [
         "^svn\\:\\/\\/svn\\.chromium\\.org\\/chrome/trunk/src(|/.*)$",
@@ skipping 18 matching lines @@
     "verifiers_no_patch": {
         "experimental_try_job_verifier": {
             "10 percent experiment": {
                 "percentage": 0.1,
                 "trybots": {
                     "launched": {
                         "tryserver.chromium.linux": {
                             "android_amp_rel_tests_recipe": [
                                 "defaulttests"
                             ],
+                            "cast_shell_android": [
+                                "defaulttests"
+                            ],
+                            "cast_shell_linux": [
+                                "defaulttests"
+                            ],
                             "linux_arm_compile": [
                                 "defaulttests"
                             ],
                             "linux_chromium_asan_rel_ng": [
                                 "defaulttests"
                             ]
                         },
                         "tryserver.chromium.mac": {
                             "mac_chromium_gn_rel": [
                                 "defaulttests"
@@ skipping 118 matching lines @@
                         "defaulttests"
                     ],
                     "win_chromium_x64_rel_ng": [
                         "defaulttests"
                     ]
                 }
             }
         }
     }
 }