Move Code Coverage to new FYI bot

Currently, the Step module's step.nest command as used in the openscreen
trybot and the code_coverage module does not function as documented:
https://cs.corp.google.com/github/luci/recipes-py/recipe_modules/step/api.py?fromv2=true&l=208

This is a known issue and is being tracked by bug:
https://bugs.chromium.org/p/chromium/issues/detail?id=1078530

Until this bug is resolved, code coverage must be calculated in a
separate trybot, or issues in code coverage can cause an otherwise
passing trybot to fail. This CL adds an FYI bot to calculate code
coverage, and removed the code coverage mixin from existing required
bots.

Change-Id: I47a9bf8429ce424262660b13911e1f14d14f49e4
Reviewed-on: https://chromium-review.googlesource.com/c/openscreen/+/2182316
Commit-Queue: Ryan Keane <rwkeane@google.com>
Reviewed-by: Jordan Bayles <jophba@chromium.org>
Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Reviewed-by: Brandon Tolsch <btolsch@chromium.org>
diff --git a/infra/config/global/cr-buildbucket.cfg b/infra/config/global/cr-buildbucket.cfg
index f0255a4..31ef94b 100644
--- a/infra/config/global/cr-buildbucket.cfg
+++ b/infra/config/global/cr-buildbucket.cfg
@@ -158,7 +158,6 @@
       mixins: "debug"
       mixins: "x64"
       mixins: "asan"
-      mixins: "code_coverage"
     }
 
     builders {
@@ -206,6 +205,16 @@
       mixins: "x64"
       mixins: "chromium"
     }
+
+    # TODO(issuetracker.google.com/155812080): Integrate this with existing
+    # linux64_debug bot.
+    builders {
+      name: "linux64_coverage_debug"
+      mixins: "linux"
+      mixins: "debug"
+      mixins: "x64"
+      mixins: "code_coverage"
+    }
   }
 }
 
@@ -246,7 +255,6 @@
       mixins: "debug"
       mixins: "x64"
       mixins: "asan"
-      mixins: "code_coverage"
     }
 
     builders {
diff --git a/infra/config/global/luci-milo.cfg b/infra/config/global/luci-milo.cfg
index d59820c..974670a 100644
--- a/infra/config/global/luci-milo.cfg
+++ b/infra/config/global/luci-milo.cfg
@@ -48,6 +48,12 @@
     category: "chromium fyi"
     short_name: "mac"
   }
+
+  builders {
+    name: "buildbucket/luci.openscreen.ci/code_coverage"
+    category: "linux|x64"
+    short_name: "coverage"
+  }
 }
 
 consoles {
@@ -98,4 +104,10 @@
     category: "chromium fyi"
     short_name: "mac"
   }
+
+  builders {
+    name: "buildbucket/luci.openscreen.try/code_coverage"
+    category: "linux|x64"
+    short_name: "coverage"
+  }
 }
diff --git a/infra/config/global/luci-scheduler.cfg b/infra/config/global/luci-scheduler.cfg
index 6389f22..dfe8b6a 100644
--- a/infra/config/global/luci-scheduler.cfg
+++ b/infra/config/global/luci-scheduler.cfg
@@ -27,6 +27,7 @@
   triggers: "linux64_tsan"
   triggers: "linux_arm64_debug"
   triggers: "mac_debug"
+  triggers: "code_coverage"
 }
 
 trigger {
@@ -110,3 +111,13 @@
     builder: "chromium_mac_debug"
   }
 }
+
+job {
+  id: "code_coverage"
+  acl_sets: "default"
+  buildbucket: {
+    server: "cr-buildbucket.appspot.com"
+    bucket: "luci.openscreen.ci"
+    builder: "code_coverage"
+  }
+}