Bug 1654817: Part 2 - Bump dom.ipc.processCount pref to 3 on Nightly; r=geckoview-reviewers,agi

I want to start with 3 so that we initially get a good look at how things run
with multiple processes, but when we easily hit the limit. We'll increase to
our final process count in a future bug.

Differential Revision: https://phabricator.services.mozilla.com/D94884

mobile/android/app/geckoview-prefs.js

@@ -19,7 +19,13 @@ pref("privacy.trackingprotection.pbmode.enabled", false);
 
 pref("browser.tabs.remote.autostart", true);
 pref("dom.ipc.keepProcessesAlive.web", 1);
-pref("dom.ipc.processCount", 1);
+
+#ifdef RELEASE_OR_BETA
+  pref("dom.ipc.processCount", 1);
+#else
+  pref("dom.ipc.processCount", 3);
+#endif
+
 pref("dom.ipc.processPrelaunch.enabled", false);
 
 // Don't create the hidden window during startup.