diff -r 000000000000 -r 6474c204b198 dom/plugins/test/mochitest/utils.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/plugins/test/mochitest/utils.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,44 @@
+function paintCountIs(plugin, expected, msg) {
+  var count = plugin.getPaintCount();
+  var realExpected = expected;
+  var isAsync = SimpleTest.testPluginIsOOP();
+  if (isAsync) {
+    ++realExpected; // extra paint at startup for all async-rendering plugins
+  } else {
+    try {
+      if (SpecialPowers.Cc["@mozilla.org/gfx/info;1"].getService(SpecialPowers.Ci.nsIGfxInfo).D2DEnabled) {
+        realExpected *= 2;
+      }
+    } catch (e) {}
+  }
+  ok(realExpected == count, msg + " (expected " + expected +
+     " independent paints, expected " + realExpected + " logged paints, got " +
+     count + " actual paints)");
+}
+
+function getTestPlugin(pluginName) {
+  var ph = SpecialPowers.Cc["@mozilla.org/plugin/host;1"]
+                                 .getService(SpecialPowers.Ci.nsIPluginHost);
+  var tags = ph.getPluginTags();
+  var name = pluginName || "Test Plug-in";
+  for (var tag of tags) {
+    if (tag.name == name) {
+      return tag;
+    }
+  }
+
+  ok(false, "Could not find plugin tag with plugin name '" + name + "'");
+  return null;
+}
+
+// call this to set the test plugin(s) initially expected enabled state.
+// it will automatically be reset to it's previous value after the test
+// ends
+function setTestPluginEnabledState(newEnabledState, pluginName) {
+  var plugin = getTestPlugin(pluginName);
+  var oldEnabledState = plugin.enabledState;
+  plugin.enabledState = newEnabledState;
+  SimpleTest.registerCleanupFunction(function() {
+    getTestPlugin(pluginName).enabledState = oldEnabledState;
+  });
+}