Enable Android swarming for content_browsertests.

testing/buildbot/chromium.linux.json

 {
   "Android GN": {
     "additional_compile_targets": [
       "all"
     ],
     "gtest_tests": [
       {
         "test": "android_webview_unittests"
       },
       {
@@ skipping 155 matching lines @@
         ],
         "test": "components_browsertests"
       },
       {
         "args": [
           "--isolate_file_path=src/components/components_unittests.isolate"
         ],
         "test": "components_unittests"
       },
       {
-        "args": [
-          "--isolate_file_path=src/content/content_browsertests.isolate"
-        ],
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "content_browsertests"
       },
       {
         "args": [
           "--isolate_file_path=src/content/content_unittests.isolate"
         ],
         "test": "content_unittests"
       },
       {
         "test": "device_unittests"
@@ skipping 1484 matching lines @@
       }
     ],
     "scripts": [
       {
         "name": "nacl_integration",
         "script": "nacl_integration.py"
       }
     ]
   }
 }