Bug 979446 - Disable dom/downloads tests on B2G for frequent timeouts.

testing/mochitest/b2g-debug.json

@@ -14,6 +14,7 @@
     "dom/apps":"bug 972927, nearly perma-fail",
     "dom/datastore":"bug 974270, frequent failures",
     "dom/datastore/tests/test_changes.html":"intermittent failures, bug 961021",
+    "dom/downloads":"bug 979446, frequent failures",
     "dom/tests/mochitest/general/test_focusrings.xul":"",
     "layout/base/tests/test_bug465448.xul":"",
 

testing/mochitest/b2g-desktop.json

@@ -12,6 +12,7 @@
     "b2g/chrome/content/test/mochitest": "require OOP support for mochitest-b2g-desktop, Bug 957554",
     "content/xul":"tests that use xul",
     "layout/xul" : "",
+    "dom/downloads":"bug 979446, frequent failures",
     "dom/plugins": "tests that use plugins",
     "dom/tests/mochitest/general/test_focusrings.xul":"",
     "layout/base/tests/test_bug465448.xul":"",

testing/mochitest/b2g.json

@@ -13,6 +13,7 @@
     "layout/xul" : "",
     "dom/apps":"bug 972927, nearly perma-fail",
     "dom/datastore":"bug 974270, frequent failures",
+    "dom/downloads":"bug 979446, frequent failures",
     "dom/tests/mochitest/general/test_focusrings.xul":"",
     "layout/base/tests/test_bug465448.xul":"",