Bug 1416711 - Remove default values for registerActors;r=ochameau

The default values for registerActors are never used in the codebase
and feel counter intuitive as they set all booleans to true.

MozReview-Commit-ID: 25zaJss9E4R

--HG--
extra : rebase_source : 9cbbd8ea44d7cc64bb17ada5c06cc1b7b016067b

devtools/server/main.js

@@ -265,8 +265,7 @@ var DebuggerServer = {
    *        "windowtype" attribute of the main chrome windows. Used by some
    *        actors to retrieve them.
    */
-  registerActors({ root = true, browser = true, tab = true,
-                   windowType = null }) {
+  registerActors({ root, browser, tab, windowType }) {
     if (windowType) {
       this.chromeWindowType = windowType;
     }