Revert "Merge from vscode 81d7885dc2e9dc617e1522697a2966bc4025a45d (#5949)" (#5983)

This reverts commit d15a3fcc98.

src/vs/platform/extensions/common/extensions.ts

@@ -3,6 +3,7 @@
  *  Licensed under the Source EULA. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
+import { areSameExtensions } from 'vs/platform/extensionManagement/common/extensionManagementUtil';
 import * as strings from 'vs/base/common/strings';
 import { ILocalization } from 'vs/platform/localizations/common/localizations';
 import { URI } from 'vs/base/common/uri';
@@ -108,6 +109,24 @@ export interface IExtensionContributions {
 
 export type ExtensionKind = 'ui' | 'workspace';
 
+export class ExtensionIdentifierWithVersion {
+	constructor(
+		readonly identifier: IExtensionIdentifier,
+		readonly version: string
+	) { }
+
+	key(): string {
+		return `${this.identifier.id}-${this.version}`;
+	}
+
+	equals(o: any): boolean {
+		if (!(o instanceof ExtensionIdentifierWithVersion)) {
+			return false;
+		}
+		return areSameExtensions(this.identifier, o.identifier) && this.version === o.version;
+	}
+}
+
 export function isIExtensionIdentifier(thing: any): thing is IExtensionIdentifier {
 	return thing
 		&& typeof thing === 'object'