Deprecate Chart.{Type} classes (#5868)

It looks like these classes are a legacy from version 1 but we actually never promoted their usage. Instead, the regular way to create a chart is to set the type in the config, for example: `new Chart(ctx, {type: 'bar'})`. Some types are actually missing (no `Chart.HorizontalBar` or `Chart.Pie`) but it's also not scalable because it can easily conflict with other classes scoped under the `Chart` namespace.

src/chart.js

@@ -42,14 +42,6 @@ require('./controllers/controller.polarArea')(Chart);
 require('./controllers/controller.radar')(Chart);
 require('./controllers/controller.scatter')(Chart);
 
-require('./charts/Chart.Bar')(Chart);
-require('./charts/Chart.Bubble')(Chart);
-require('./charts/Chart.Doughnut')(Chart);
-require('./charts/Chart.Line')(Chart);
-require('./charts/Chart.PolarArea')(Chart);
-require('./charts/Chart.Radar')(Chart);
-require('./charts/Chart.Scatter')(Chart);
-
 // Loading built-in plugins
 var plugins = require('./plugins');
 for (var k in plugins) {
@@ -116,8 +108,33 @@ Chart.canvasHelpers = Chart.helpers.canvas;
 /**
  * Provided for backward compatibility, use Chart.layouts instead.
  * @namespace Chart.layoutService
- * @deprecated since version 2.8.0
+ * @deprecated since version 2.7.3
  * @todo remove at version 3
  * @private
  */
 Chart.layoutService = Chart.layouts;
+
+/**
+ * Provided for backward compatibility, instead we should create a new Chart
+ * by setting the type in the config (`new Chart(id, {type: '{chart-type}'}`).
+ * @deprecated since version 2.8.0
+ * @todo remove at version 3
+ */
+Chart.helpers.each(
+	[
+		'Bar',
+		'Bubble',
+		'Doughnut',
+		'Line',
+		'PolarArea',
+		'Radar',
+		'Scatter'
+	],
+	function(klass) {
+		Chart[klass] = function(ctx, cfg) {
+			return new Chart(ctx, Chart.helpers.merge(cfg || {}, {
+				type: klass.charAt(0).toLowerCase() + klass.slice(1)
+			}));
+		};
+	}
+);

test/specs/global.deprecations.tests.js

@@ -1,5 +1,32 @@
 describe('Deprecations', function() {
 	describe('Version 2.8.0', function() {
+		[
+			['Bar', 'bar'],
+			['Bubble', 'bubble'],
+			['Doughnut', 'doughnut'],
+			['Line', 'line'],
+			['PolarArea', 'polarArea'],
+			['Radar', 'radar'],
+			['Scatter', 'scatter']
+		].forEach(function(descriptor) {
+			var klass = descriptor[0];
+			var type = descriptor[1];
+
+			describe('Chart.' + klass, function() {
+				it('should be defined as a function', function() {
+					expect(Chart[klass]).toBeDefined();
+					expect(typeof Chart[klass]).toBe('function');
+				});
+				it('should create a chart of type "' + type + '"', function() {
+					var chart = new Chart[klass]('foo', {data: {}});
+					expect(chart instanceof Chart.Controller).toBeTruthy();
+					expect(chart.config.type).toBe(type);
+				});
+			});
+		});
+	});
+
+	describe('Version 2.7.3', function() {
 		describe('Chart.layoutService', function() {
 			it('should be defined and an alias of Chart.layouts', function() {
 				expect(Chart.layoutService).toBeDefined();