Fix microsoft/vscode#34615 - don't show error message for sending a m…

…essage to the target after close. This can happen in lots of places, like anywhere that we do something asynchronously after sourcemaps load.

src/chrome/chromeConnection.ts

@@ -66,9 +66,13 @@ class LoggingSocket extends WebSocket {
     }
 
     public send(data: any, opts?: any, cb?: (err: Error) => void): void {
-        super.send.apply(this, arguments);
-
         const msgStr = JSON.stringify(data);
+        if (this.readyState !== WebSocket.OPEN) {
+            logger.log(`→ Warning: Target not open! Message: ${msgStr}`);
+            return;
+        }
+
+        super.send.apply(this, arguments);
         logger.verbose('→ To target: ' + msgStr);
     }
 }

src/chrome/chromeDebugAdapter.ts

@@ -613,6 +613,10 @@ export abstract class ChromeDebugAdapter implements IDebugAdapter {
 
         const mappedUrl = this._pathTransformer.scriptParsed(script.url);
         const sourceMapsP = this._sourceMapTransformer.scriptParsed(mappedUrl, script.sourceMapURL).then(sources => {
+            if (this._hasTerminated) {
+                return undefined;
+            }
+
             if (sources) {
                 sources
                     .filter(source => source !== mappedUrl) // Tools like babel-register will produce sources with the same path as the generated script