Added empty kernel and hook up with Kernel drop down (#3173)

* Initial toolbar work
- This is in-progress and needs additional fixes

* Resolve PR comments

* Added empty kernel and hook up with Kernel dropdown

* Resolve PR comments

src/sql/parts/notebook/notebookActions.ts

@@ -0,0 +1,87 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+ import * as sqlops from 'sqlops';
+
+import { Action } from 'vs/base/common/actions';
+import { TPromise } from 'vs/base/common/winjs.base';
+import { localize } from 'vs/nls';
+import { IContextViewProvider } from 'vs/base/browser/ui/contextview/contextview';
+
+import { SelectBox } from 'sql/base/browser/ui/selectBox/selectBox';
+import { INotebookModel } from 'sql/parts/notebook/models/modelInterfaces';
+
+const msgLoading = localize('loading', 'Loading kernels...');
+export class AddCellAction extends Action {
+	public static ID = 'notebook.addCell';
+	public static LABEL = 'Cell';
+
+	constructor(
+	) {
+		super(AddCellAction.ID, AddCellAction.LABEL, 'newStepIcon');
+	}
+
+	public run(context: any): TPromise<boolean> {
+		return new TPromise<boolean>((resolve, reject) => {
+			try {
+				resolve(true);
+			} catch (e) {
+				reject(e);
+			}
+		});
+	}
+}
+
+export class KernelsDropdown extends SelectBox {
+	private model: INotebookModel;
+	constructor(contextViewProvider: IContextViewProvider, modelRegistered: Promise<INotebookModel>
+	) {
+		super( [msgLoading], msgLoading, contextViewProvider);
+		if (modelRegistered) {
+			modelRegistered
+			.then((model) => this.updateModel(model))
+			.catch((err) => {
+				// No-op for now
+			});
+		}
+
+		this.onDidSelect(e => this.doChangeKernel(e.selected));
+	}
+
+	updateModel(model: INotebookModel): void {
+		this.model = model;
+		model.kernelsChanged((defaultKernel) => {
+			this.updateKernel(defaultKernel);
+		});
+		if (model.clientSession) {
+			model.clientSession.kernelChanged((changedArgs: sqlops.nb.IKernelChangedArgs) => {
+				if (changedArgs.newValue) {
+					this.updateKernel(changedArgs.newValue);
+				}
+			});
+		}
+	}
+
+	// Update SelectBox values
+	private updateKernel(defaultKernel: sqlops.nb.IKernelSpec) {
+		let specs = this.model.specs;
+		if (specs && specs.kernels) {
+			let index = specs.kernels.findIndex((kernel => kernel.name === defaultKernel.name));
+			this.setOptions(specs.kernels.map(kernel => kernel.display_name), index);
+		}
+	}
+
+	public doChangeKernel(displayName: string): void {
+		this.model.changeKernel(displayName);
+	}
+}
+
+export class AttachToDropdown extends SelectBox {
+	constructor(contextViewProvider: IContextViewProvider
+	) {
+		let options: string[] = ['localhost'];
+		super(options, 'localhost', contextViewProvider);
+	}
+}