chromium_tests: require explicit compile targets (except for Android)

scripts/slave/recipe_modules/chromium_tests/api.py

Index: scripts/slave/recipe_modules/chromium_tests/api.py
diff --git a/scripts/slave/recipe_modules/chromium_tests/api.py b/scripts/slave/recipe_modules/chromium_tests/api.py
index d628116a6caf786afa21c018d77b724286d89a12..cdbf2f67881db5164142df04591a990a0484622d 100644
--- a/scripts/slave/recipe_modules/chromium_tests/api.py
+++ b/scripts/slave/recipe_modules/chromium_tests/api.py
@@ -468,6 +468,12 @@ class ChromiumTestsApi(recipe_api.RecipeApi):
       )
 
   def run_mb_and_compile(self, compile_targets, isolated_targets, name_suffix):
+    # TODO(phajdan.jr): Also enable error on android.
+    if not compile_targets and self.m.chromium.c.TARGET_PLATFORM != 'android':
+      # TODO(phajdan.jr): Mark as infra failure (make python module support it).
+      self.m.python.failing_step(
+          'compile', 'Please add explicit compile targets for the build')
+
     if self.m.chromium.c.project_generator.tool == 'mb':
       # We don't use the mastername and buildername passed in, because
       # those may be the values of the continuous builder the trybot may