[Android] Add chrome_public_test_apk on android_n5x_swarming_rel

testing/buildbot/chromium.android.json

 {
   "Android Cronet Builder": {
     "additional_compile_targets": [
       "cronet_package"
     ]
   },
   "Android N5X Swarm Builder": {
     "gtest_tests": [
       {
         "args": [
@@ skipping 218 matching lines @@
                 "=android%2Fswarming%2Flogcats%2F",
                 "${TASK_ID}%2F%2B%2Funified_logcats"
               ],
               "name": "shard #${SHARD_INDEX} logcats"
             }
           ]
         },
         "test": "cc_unittests"
       },
       {
+        "merge": {
+          "args": [
+            "--bucket",
+            "chromium-result-details",
+            "--test-name",
+            "chrome_public_test_apk"
+          ],
+          "script": "//build/android/pylib/results/presentation/test_results_presentation.py"
+        },
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "cipd_packages": [
+            {
+              "cipd_package": "infra/tools/luci/logdog/butler/${platform}",
+              "location": "bin",
+              "revision": "git_revision:ff387eadf445b24c935f1cf7d6ddd279f8a6b04c"
+            }
+          ],
+          "dimension_sets": [
+            {
+              "android_devices": "6",

[shenghuazhang, 2017/06/16 00:32:25]

Some of the "android_devices" set "4", some of them set with "6". Is "6" proper
here?

+              "device_os": "MMB29Q",
+              "device_type": "bullhead"
+            }
+          ],
+          "expiration": 10800,
+          "hard_timeout": 1800,
+          "output_links": [
+            {
+              "link": [
+                "https://luci-logdog.appspot.com/v/?s",
+                "=android%2Fswarming%2Flogcats%2F",
+                "${TASK_ID}%2F%2B%2Funified_logcats"
+              ],
+              "name": "shard #${SHARD_INDEX} logcats"
+            }
+          ]
+        },
+        "test": "chrome_public_test_apk"
+      },
+      {
         "args": [
           "--shared-prefs-file=../../chrome/android/shared_preference_files/test/vr_cardboard_skipdon_setupcomplete.json",
           "--additional-apk=../../third_party/gvr-android-sdk/test-apks/vr_services/vr_services_current.apk"
         ],
         "merge": {
           "args": [
             "--bucket",
             "chromium-result-details",
             "--test-name",
             "chrome_public_test_vr_apk"
@@ skipping 8178 matching lines @@
               "name": "shard #${SHARD_INDEX} logcats"
             }
           ],
           "shards": 6
         },
         "test": "webview_instrumentation_test_apk"
       }
     ]
   }
 }