Merge from vscode 1eb87b0e9ce9886afeaecec22b31abd0d9b7939f (#7282)

* Merge from vscode 1eb87b0e9ce9886afeaecec22b31abd0d9b7939f

* fix various icon issues

* fix preview features

src/vs/workbench/services/textfile/browser/browserTextFileService.ts

@@ -0,0 +1,62 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { AbstractTextFileService } from 'vs/workbench/services/textfile/browser/textFileService';
+import { ITextFileService, IResourceEncodings, IResourceEncoding, ModelState } from 'vs/workbench/services/textfile/common/textfiles';
+import { registerSingleton } from 'vs/platform/instantiation/common/extensions';
+import { ShutdownReason } from 'vs/platform/lifecycle/common/lifecycle';
+import { Schemas } from 'vs/base/common/network';
+
+export class BrowserTextFileService extends AbstractTextFileService {
+
+	readonly encoding: IResourceEncodings = {
+		getPreferredWriteEncoding(): IResourceEncoding {
+			return { encoding: 'utf8', hasBOM: false };
+		}
+	};
+
+	protected onBeforeShutdown(reason: ShutdownReason): boolean {
+		// Web: we cannot perform long running in the shutdown phase
+		// As such we need to check sync if there are any dirty files
+		// that have not been backed up yet and then prevent the shutdown
+		// if that is the case.
+		return this.doBeforeShutdownSync();
+	}
+
+	private doBeforeShutdownSync(): boolean {
+		if (this.models.getAll().some(model => model.hasState(ModelState.PENDING_SAVE) || model.hasState(ModelState.PENDING_AUTO_SAVE))) {
+			return true; // files are pending to be saved: veto
+		}
+
+		const dirtyResources = this.getDirty();
+		if (!dirtyResources.length) {
+			return false; // no dirty: no veto
+		}
+
+		if (!this.isHotExitEnabled) {
+			return true; // dirty without backup: veto
+		}
+
+		for (const dirtyResource of dirtyResources) {
+			let hasBackup = false;
+
+			if (this.fileService.canHandleResource(dirtyResource)) {
+				const model = this.models.get(dirtyResource);
+				hasBackup = !!(model && model.hasBackup());
+			} else if (dirtyResource.scheme === Schemas.untitled) {
+				hasBackup = this.untitledEditorService.hasBackup(dirtyResource);
+			}
+
+			if (!hasBackup) {
+				console.warn('Unload prevented: pending backups');
+				return true; // dirty without backup: veto
+			}
+		}
+
+		return false; // dirty with backups: no veto
+	}
+}
+
+registerSingleton(ITextFileService, BrowserTextFileService);