Swarm tests on Linux release tester.

BUG=414808
TBR=maruel@chromium.org
NOTRY=true

Committed: https://chromium.googlesource.com/chromium/src/+/01b2eb0b5e291faa238d6a21def3e62056bc1fdd

Review URL: https://codereview.chromium.org/598053002

Cr-Commit-Position: refs/heads/master@{#296499}

testing/buildbot/chromium.linux.json

@@ -5,16 +5,37 @@
       "app_list_unittests",
       "app_shell_browsertests",
       "aura_unittests",
-      "base_unittests",
-      "browser_tests",
+      {
+        "test": "base_unittests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
+      {
+        "test": "browser_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 5
+        }
+      },
       "cacheinvalidation_unittests",
       "cast_unittests",
       "cc_unittests",
       "chromedriver_unittests",
       "components_unittests",
       "compositor_unittests",
-      "content_browsertests",
-      "content_unittests",
+      {
+        "test": "content_browsertests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
+      {
+        "test": "content_unittests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
       "crypto_unittests",
       "dbus_unittests",
       "device_unittests",
@@ -25,7 +46,12 @@
       "gfx_unittests",
       "google_apis_unittests",
       "gpu_unittests",
-      "interactive_ui_tests",
+      {
+        "test": "interactive_ui_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
       "ipc_mojo_unittests",
       "ipc_tests",
       "jingle_unittests",
@@ -42,16 +68,31 @@
       "mojo_system_unittests",
       "mojo_view_manager_unittests",
       "nacl_loader_unittests",
-      "net_unittests",
+      {
+        "test": "net_unittests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
       "ppapi_unittests",
       "printing_unittests",
       "remoting_unittests",
       "sandbox_linux_unittests",
       "sql_unittests",
       "ui_unittests",
-      "sync_integration_tests",
+      {
+        "test": "sync_integration_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
       "sync_unit_tests",
-      "unit_tests",
+      {
+        "test": "unit_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
       "url_unittests",
       "views_unittests",
       "wm_unittests"
@@ -193,7 +234,12 @@
       "mojo_system_unittests",
       "mojo_view_manager_unittests",
       "nacl_loader_unittests",
-      "net_unittests",
+      {
+        "test": "net_unittests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
       "ppapi_unittests",
       "printing_unittests",
       "remoting_unittests",