Unexpected behaviors when actions happen before INIT

[Mardak]

In investigating #3695 for the actual cause for #3377, turns out if Activity Stream is late to load and simulates a NEW_TAB_INIT/LOAD for existing pages, those might happen before INIT, which theoretically should be the very first action?

Here createChannel simulates "RemotePage:Init" and "RemotePage:Load" before "INIT". I guess ActivityStreamMessageChannel should only simulate after INIT?

activity-stream/system-addon/lib/Store.jsm

Lines 135 to 139 in 9327fcc

	this._messageChannel.createChannel();
	// Dispatch an initial action after all enabled feeds are ready
	if (initAction) {
	this.dispatch(initAction);

@k88hudson

[piatra]

Fixed by #3695.