Merge from vscode 731f9c25632dbbf01ee3a7892ad9d2791fe0260c

src/vs/platform/telemetry/common/telemetry.ts

@@ -46,6 +46,8 @@ export interface ITelemetryService {
 
 	getTelemetryInfo(): Promise<ITelemetryInfo>;
 
+	setExperimentProperty(name: string, value: string): void;
+
 	isOptedIn: boolean;
 }
 

src/vs/platform/telemetry/common/telemetryService.ts

@@ -31,6 +31,7 @@ export class TelemetryService implements ITelemetryService {
 
 	private _appender: ITelemetryAppender;
 	private _commonProperties: Promise<{ [name: string]: any; }>;
+	private _experimentProperties: { [name: string]: string } = {};
 	private _piiPaths: string[];
 	private _userOptIn: boolean;
 	private _enabled: boolean;
@@ -79,6 +80,10 @@ export class TelemetryService implements ITelemetryService {
 		}
 	}
 
+	setExperimentProperty(name: string, value: string): void {
+		this._experimentProperties[name] = value;
+	}
+
 	setEnabled(value: boolean): void {
 		this._enabled = value;
 	}
@@ -119,6 +124,9 @@ export class TelemetryService implements ITelemetryService {
 			// (first) add common properties
 			data = mixin(data, values);
 
+			// (next) add experiment properties
+			data = mixin(data, this._experimentProperties);
+
 			// (last) remove all PII from data
 			data = cloneAndChange(data, value => {
 				if (typeof value === 'string') {

src/vs/platform/telemetry/common/telemetryUtils.ts

@@ -28,6 +28,7 @@ export const NullTelemetryService = new class implements ITelemetryService {
 		return this.publicLogError(eventName, data as ITelemetryData);
 	}
 
+	setExperimentProperty() { }
 	setEnabled() { }
 	isOptedIn = true;
 	getTelemetryInfo(): Promise<ITelemetryInfo> {