Bug 1395903 - Stop using sdk/core/heritage in devtools performance server recorder.js.r=jdescottes

MozReview-Commit-ID: BdYVlQVvClN

--HG--
extra : rebase_source : c4851c0d9fb227f14b00f8107aa40e11478d58b6

devtools/server/performance/recorder.js

@@ -8,8 +8,6 @@ const { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "Services");
 loader.lazyRequireGetter(this, "promise");
-loader.lazyRequireGetter(this, "Class",
-  "sdk/core/heritage", true);
 loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
 
 loader.lazyRequireGetter(this, "Memory",