[Chromecast] Enabled running unit tests for //cc on presubmits

BUG=internal b/22512618
TEST=Unit tests passed on cast targets

Change-Id: Ia19432ec97343a95777b3580b5d99e0f594ba3ae
Reviewed-on: https://chromium-review.googlesource.com/569678Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Commit-Queue: Sandeep Vijayasekar <sandv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486923}

chromecast/BUILD.gn

@@ -30,6 +30,7 @@ cast_test_group("cast_tests") {
   filters = []
   tests = [
     "//base:base_unittests",
+    "//cc:cc_unittests",
     "//chromecast/base:cast_base_unittests",
     "//chromecast/base/component:cast_component_unittests",
     "//chromecast/crypto:cast_crypto_unittests",