[explore] Split large reducer logic in ExploreViewContainer (#3088)

* split reducer logic for ExploreViewContainer

* fix saveModal component and unit tests

* revert changes in SaveModal_spec.
will make another commit just to improve test coverage for SaveModal component.

* remove comment-out code

* fix merge confilicts

superset/assets/spec/javascripts/explore/chartActions_spec.js

@@ -0,0 +1,36 @@
+import { it, describe } from 'mocha';
+import { expect } from 'chai';
+import sinon from 'sinon';
+import $ from 'jquery';
+import * as exploreUtils from '../../../javascripts/explore/exploreUtils';
+import * as actions from '../../../javascripts/explore/actions/chartActions';
+
+describe('chart actions', () => {
+  let dispatch;
+  let urlStub;
+  let ajaxStub;
+  let request;
+
+  beforeEach(() => {
+    dispatch = sinon.spy();
+    urlStub = sinon.stub(exploreUtils, 'getExploreUrl').callsFake(() => ('mockURL'));
+    ajaxStub = sinon.stub($, 'ajax');
+  });
+
+  afterEach(() => {
+    urlStub.restore();
+    ajaxStub.restore();
+  });
+
+  it('should handle query timeout', () => {
+    ajaxStub.yieldsTo('error', { statusText: 'timeout' });
+    request = actions.runQuery({});
+    request(dispatch, sinon.stub().returns({
+      explore: {
+        controls: [],
+      },
+    }));
+    expect(dispatch.callCount).to.equal(3);
+    expect(dispatch.args[0][0].type).to.equal(actions.CHART_UPDATE_TIMEOUT);
+  });
+});