Add angle_unittests to ozone tests.

Without this, nothing is compiling ANGLE's Ozone back end.

BUG=angleproject:1412

Review-Url: https://codereview.chromium.org/2385603002
Cr-Commit-Position: refs/heads/master@{#422982}

BUILD.gn

@@ -302,6 +302,8 @@ group("both_gn_and_gyp") {
       "//mojo/edk/test:mojo_public_system_unittests",
       "//net:net_perftests",
       "//services/shell/public/cpp",
+      "//third_party/angle/src/tests:angle_end2end_tests",
+      "//third_party/angle/src/tests:angle_unittests",
       "//third_party/WebKit/Source/platform:blink_platform_unittests",
       "//third_party/WebKit/Source/platform/heap:blink_heap_unittests",
       "//third_party/WebKit/Source/web:webkit_unit_tests",
@@ -533,8 +535,6 @@ group("both_gn_and_gyp") {
       "//ipc:ipc_perftests",
       "//media:media_perftests",
       "//net:dump_cache",
-      "//third_party/angle/src/tests:angle_end2end_tests",
-      "//third_party/angle/src/tests:angle_unittests",
       "//third_party/codesighs:maptsvdifftool",
       "//third_party/libphonenumber:libphonenumber_unittests",
       "//ui/compositor:compositor_unittests",

testing/buildbot/chromium.chromiumos.json

@@ -12,6 +12,12 @@
         },
         "test": "accessibility_unittests"
       },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
+        "test": "angle_unittests"
+      },
       {
         "swarming": {
           "can_use_on_swarming_builders": true