[chromecast] Make testnames consistent.

chromecast/app/BUILD.gn

Index: chromecast/app/BUILD.gn
diff --git a/chromecast/app/BUILD.gn b/chromecast/app/BUILD.gn
index ffc10702936d590935602ba01b3fcb17d9ebd0f8..7f0f44fb9336ee7d04782fbc1ff1f8e4b548e71b 100644
--- a/chromecast/app/BUILD.gn
+++ b/chromecast/app/BUILD.gn
@@ -56,8 +56,23 @@ source_set("cast_crash_client") {
   }
 }
 
-# TODO(kmackay) Consider renaming this.
-test("cast_shell_unittests") {
+source_set("test_support") {
+  testonly = true
+  sources = [
+    "cast_test_launcher.cc",
+  ]
+
+  deps = [
+    ":app",
+    "//base",
+    "//base/test:test_support",
+    "//chromecast/base",
+    "//content/test:test_support",
+  ]
+}
+
+source_set("unittests") {
+  testonly = true
   sources = [
     "linux/cast_crash_reporter_client_unittest.cc",
   ]
@@ -65,7 +80,6 @@ test("cast_shell_unittests") {
   deps = [
     ":cast_crash_client",
     "//base",
-    "//base/test:run_all_unittests",
     "//base/test:test_support",
     "//chromecast/base:test_support",
     "//chromecast/crash",