Pull render service off instantiation service safely

src/common/services/InstantiationService.ts

@@ -36,7 +36,7 @@ export class ServiceCollection {
     return this._entries.has(id);
   }
 
-  get<T>(id: IServiceIdentifier<T>): T {
+  get<T>(id: IServiceIdentifier<T>): T | undefined {
     return this._entries.get(id);
   }
 }
@@ -52,6 +52,10 @@ export class InstantiationService implements IInstantiationService {
     this._services.set(id, instance);
   }
 
+  public getService<T>(id: IServiceIdentifier<T>): T | undefined {
+    return this._services.get(id);
+  }
+
   public createInstance<T>(ctor: any, ...args: any[]): any {
     const serviceDependencies = getServiceDependencies(ctor).sort((a, b) => a.index - b.index);
 

src/common/services/Services.ts

@@ -171,6 +171,7 @@ export interface IConstructorSignature8<A1, A2, A3, A4, A5, A6, A7, A8, T> {
 export const IInstantiationService = createDecorator<IInstantiationService>('InstantiationService');
 export interface IInstantiationService {
   setService<T>(id: IServiceIdentifier<T>, instance: T): void;
+  getService<T>(id: IServiceIdentifier<T>): T | undefined;
 
   createInstance<T>(ctor: IConstructorSignature0<T>): T;
   createInstance<A1, T>(ctor: IConstructorSignature1<A1, T>, first: A1): T;