Remove support for the keygen tag

chromecast/BUILD.gn

Index: chromecast/BUILD.gn
diff --git a/chromecast/BUILD.gn b/chromecast/BUILD.gn
index 0ecc41f8aae0953918369fd36aa3ad163d36a072..56cec5d94303bb1b832dfd16ffd5e9de6c183e95 100644
--- a/chromecast/BUILD.gn
+++ b/chromecast/BUILD.gn
@@ -218,17 +218,11 @@ cast_test_group("cast_tests") {
       gtest_excludes = [ "*" ]
     } else if (target_os == "linux" && !is_cast_desktop_build) {
       # Run net_unittests first to avoid random failures due to slow python startup
-      # KeygenHandlerTest.SmokeTest and KeygenHandlerTest.ConcurrencyTest fail due to
-      # readonly certdb (b/8153161)
       # URLRequestTestHTTP.GetTest_ManyCookies takes roughly 55s to run. Increase
       # timeout to 90s from 45s to allow it to pass (b/19821476)
       # ProxyScriptFetcherImplTest.HttpMimeType is flaking (b/19848784)
       # Running a batch of net_unittests has high overhead. Run tests in batches of 50 to reduce number of batches (b/23156294).
-      gtest_excludes = [
-        "KeygenHandlerTest.SmokeTest",
-        "KeygenHandlerTest.ConcurrencyTest",
-        "ProxyScriptFetcherImplTest.HttpMimeType",
-      ]
+      gtest_excludes = [ "ProxyScriptFetcherImplTest.HttpMimeType" ]
       args = [
         "--test-launcher-timeout=90000",
         "--test-launcher-batch-limit=50",