debug: To reduce flashing of the path name and the way we fetch stack frame....

debug: To reduce flashing of the path name and the way we fetch stack frame. We need to compute the source name based on the other frames in the stale call stack

src/vs/workbench/parts/debug/common/debugModel.ts

@@ -346,7 +346,11 @@ export class StackFrame implements IStackFrame {
 	}
 
 	public getSpecificSourceName(): string {
-		const otherSources = this.thread.getCallStack().map(sf => sf.source).filter(s => s !== this.source);
+		// To reduce flashing of the path name and the way we fetch stack frames
+		// We need to compute the source name based on the other frames in the stale call stack
+		let callStack = (<Thread>this.thread).getStaleCallStack();
+		callStack = callStack.length > 0 ? callStack : this.thread.getCallStack();
+		const otherSources = callStack.map(sf => sf.source).filter(s => s !== this.source);
 		let suffixLength = 0;
 		otherSources.forEach(s => {
 			if (s.name === this.source.name) {
@@ -417,7 +421,7 @@ export class Thread implements IThread {
 		return this.callStack;
 	}
 
-	public getStaleCallStack(): IStackFrame[] {
+	public getStaleCallStack(): ReadonlyArray<IStackFrame> {
 		return this.staleCallStack;
 	}