Port most notebook model code over to be behind a service (#3068)

- Defines a new NotebookService in Azure Data Studio which will be used to interact with notebooks. Since notebooks can require per-file instantiation the provider is just used to create & track managers for a given URI.
- Inject this into notebook.component.ts and pass required parameters that'll be used to properly initialize a manger into the method. Actual initialization not done yet.
- Port over & recompile notebook model code
- Define most required APIs in sqlops.proposed.d.ts. In the future, these will be used by extensions to contribute their own providers.

src/sql/workbench/api/node/extHostNotebook.ts

@@ -0,0 +1,76 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import * as sqlops from 'sqlops';
+import * as vscode from 'vscode';
+import { TPromise } from 'vs/base/common/winjs.base';
+import { IMainContext } from 'vs/workbench/api/node/extHost.protocol';
+import { Disposable } from 'vs/workbench/api/node/extHostTypes';
+import { localize } from 'vs/nls';
+
+
+import { ExtHostNotebookShape, MainThreadNotebookShape, SqlMainContext } from 'sql/workbench/api/node/sqlExtHost.protocol';
+
+export class ExtHostNotebook implements ExtHostNotebookShape {
+	private static _handlePool: number = 0;
+
+	private readonly _proxy: MainThreadNotebookShape;
+	private _providers = new Map<number, sqlops.nb.NotebookProvider>();
+
+	constructor(private _mainContext: IMainContext) {
+		this._proxy = _mainContext.getProxy(SqlMainContext.MainThreadNotebook);
+	}
+
+	//#region APIs called by main thread
+	getNotebookManager(notebookUri: vscode.Uri): Thenable<number> {
+		throw new Error('Not implemented');
+	}
+	handleNotebookClosed(notebookUri: vscode.Uri): void {
+		throw new Error('Not implemented');
+	}
+
+	//#endregion
+
+	//#region APIs called by extensions
+	registerNotebookProvider(provider: sqlops.nb.NotebookProvider): vscode.Disposable {
+		if (!provider || !provider.providerId) {
+			throw new Error(localize('providerRequired', 'A NotebookProvider with valid providerId must be passed to this method'));
+		}
+		const handle = this._addNewProvider(provider);
+		this._proxy.$registerNotebookProvider(provider.providerId, handle);
+		return this._createDisposable(handle);
+	}
+	//#endregion
+
+
+	//#region private methods
+	private _createDisposable(handle: number): Disposable {
+		return new Disposable(() => {
+			this._providers.delete(handle);
+			this._proxy.$unregisterNotebookProvider(handle);
+		});
+	}
+
+	private _nextHandle(): number {
+		return ExtHostNotebook._handlePool++;
+	}
+
+	private _withProvider<A, R>(handle: number, ctor: { new(...args: any[]): A }, callback: (adapter: A) => TPromise<R>): TPromise<R> {
+		let provider = this._providers.get(handle);
+		if (!(provider instanceof ctor)) {
+			return TPromise.wrapError<R>(new Error('no adapter found'));
+		}
+		return callback(<any>provider);
+	}
+
+	private _addNewProvider(adapter: sqlops.nb.NotebookProvider): number {
+		const handle = this._nextHandle();
+		this._providers.set(handle, adapter);
+		return handle;
+	}
+	//#endregion
+}
+