lib: use queue length set via setPlotConfig

- use a default of 0 (i.e. turned off the queue by default)

Author: etpinard

src/lib/queue.js

@@ -10,6 +10,8 @@
 'use strict';
 
 var Lib = require('../lib');
+var config = require('../plot_api/plot_config');
+
 
 /**
  * Copy arg array *without* removing `undefined` values from objects.
@@ -45,8 +47,6 @@ function copyArgArray(gd, args) {
 
 var queue = {};
 
-var maxElementCount = 10;
-
 // TODO: disable/enable undo and redo buttons appropriately
 
 /**
@@ -89,7 +89,7 @@ queue.add = function(gd, undoFunc, undoArgs, redoFunc, redoArgs) {
     queueObj.redo.calls.push(redoFunc);
     queueObj.redo.args.push(redoArgs);
 
-    if(gd.undoQueue.queue.length > maxElementCount) {
+    if(gd.undoQueue.queue.length > config.queueLength) {
         gd.undoQueue.queue.shift();
         gd.undoQueue.index--;
     }

src/plot_api/plot_config.js

@@ -26,6 +26,9 @@ module.exports = {
     // we can edit titles, move annotations, etc
     editable: false,
 
+    // set the length of the undo/redo queue
+    queueLength: 0,
+
     // plot will respect layout.autosize=true and infer its container size
     autosizable: false,