Swarming: conditionally run tests on swarming in chromium_trybot recipe.

scripts/slave/recipe_modules/isolate/api.py

Index: scripts/slave/recipe_modules/isolate/api.py
diff --git a/scripts/slave/recipe_modules/isolate/api.py b/scripts/slave/recipe_modules/isolate/api.py
index c0622072c5dfd07ba89c7209cf4d8005e644bb7d..d7094c41c4236ccc822b7447d77b273aa7115a72 100644
--- a/scripts/slave/recipe_modules/isolate/api.py
+++ b/scripts/slave/recipe_modules/isolate/api.py
@@ -38,7 +38,7 @@ class IsolateApi(recipe_api.RecipeApi):
     config.gyp_env.GYP_DEFINES['test_isolation_mode'] = 'archive'
     config.gyp_env.GYP_DEFINES['test_isolation_outdir'] = self._isolate_server
 
-  def find_isolated_tests(self, build_dir, targets=None):
+  def find_isolated_tests(self, build_dir, targets=None, **kwargs):
     """Returns a step which finds all *.isolated files in a build directory.
 
     Assigns the dict {target name -> *.isolated file hash} to the swarm_hashes
@@ -48,7 +48,13 @@ class IsolateApi(recipe_api.RecipeApi):
     If |targets| is None, the step will use all *.isolated files it finds.
     Otherwise, it will verify that all |targets| are found and will use only
     them. If some expected targets are missing, will abort the build.
+
+    Also accepts step execution controlling flags (always_run, can_fail_build,
+    etc.) via kwargs.
     """
+    # Failure is fatal by default.
+    kwargs.setdefault('abort_on_failure', True)
+
     def followup_fn(step_result):
       assert isinstance(step_result.json.output, dict)
       self._isolated_tests = step_result.json.output
@@ -70,6 +76,7 @@ class IsolateApi(recipe_api.RecipeApi):
       if (not self._isolated_tests and
           step_result.presentation.status != 'FAILURE'):
         step_result.presentation.status = 'WARNING'
+
     return self.m.python(
         'find isolated tests',
         self.resource('find_isolated_tests.py'),
@@ -77,9 +84,9 @@ class IsolateApi(recipe_api.RecipeApi):
           '--build-dir', build_dir,
           '--output-json', self.m.json.output(),
         ],
-        abort_on_failure=True,
         followup_fn=followup_fn,
-        step_test_data=lambda: (self.test_api.output_json(targets)))
+        step_test_data=lambda: (self.test_api.output_json(targets)),
+        **kwargs)
 
   @property
   def isolated_tests(self):