Bug 1357867 - Land in progress OSX cross compile nightly support. r=dustin

This commit adds the target_tasks method to trigger nightlies, and the unscheduled cron entry.

MozReview-Commit-ID: ELcZcUGPg2T

--HG--
extra : rebase_source : 4c7093066d4102022a851c34a32f6ff825a5a541

.cron.yml

@@ -21,6 +21,16 @@ jobs:
             mozilla-aurora: [{hour: 7, minute: 45}]  # Buildbot uses minute 40
             # No default
 
+    - name: nightly-desktop-osx
+      job:
+          type: decision-task
+          treeherder-symbol: Nd-OSX
+          triggered-by: nightly
+          target-tasks-method: nightly_macosx
+      run-on-projects:
+          - date
+      when: [] # never (hook only)
+
     - name: nightly-android
       job:
           type: decision-task

taskcluster/taskgraph/target_tasks.py

@@ -304,3 +304,18 @@ def target_tasks_stylo(full_task_graph, parameters):
             return False
         return True
     return [l for l, t in full_task_graph.tasks.iteritems() if filter(t)]
+
+
+# nightly_linux should be refactored to be nightly_all once
+# https://bugzilla.mozilla.org/show_bug.cgi?id=1267425 dependent bugs are
+# implemented
+@_target_task('nightly_macosx')
+def target_tasks_nightly_macosx(full_task_graph, parameters):
+    """Select the set of tasks required for a nightly build of macosx. The
+    nightly build process involves a pipeline of builds, signing,
+    and, eventually, uploading the tasks to balrog."""
+    def filter(task):
+        platform = task.attributes.get('build_platform')
+        if platform in ('macosx64-nightly', ):
+            return task.attributes.get('nightly', False)
+    return [l for l, t in full_task_graph.tasks.iteritems() if filter(t)]