browser(firefox): reliably close the pipe (#3280)

browser_patches/firefox/BUILD_NUMBER

@@ -1,2 +1,2 @@
-1149
-Changed: dgozman@gmail.com Mon Aug  3 15:21:45 PDT 2020
+1150
+Changed: dgozman@gmail.com Mon Aug  3 19:37:50 PDT 2020

browser_patches/firefox/juggler/components/juggler.js

@@ -94,7 +94,11 @@ CommandLineHandler.prototype = {
       const browserHandler = new BrowserHandler(dispatcher.rootSession(), dispatcher, targetRegistry, () => {
         if (silent)
           Services.startup.exitLastWindowClosingSurvivalArea();
-        pipe.stop();
+        // Send response to the Browser.close, and then stop in the next microtask.
+        Promise.resolve().then(() => {
+          connection.onclose();
+          pipe.stop();
+        });
       });
       dispatcher.rootSession().registerHandler('Browser', browserHandler);
       loadFrameScript();

browser_patches/firefox/juggler/pipe/nsRemoteDebuggingPipe.cpp

@@ -128,12 +128,14 @@ nsresult nsRemoteDebuggingPipe::Stop() {
 #if defined(_WIN32)
   CancelIoEx(readHandle, nullptr);
   CloseHandle(readHandle);
+  CloseHandle(writeHandle);
 #else
   shutdown(readFD, SHUT_RDWR);
+  shutdown(writeFD, SHUT_RDWR);
 #endif
   mReaderThread->Shutdown();
   mReaderThread = nullptr;
-  mWriterThread->AsyncShutdown();
+  mWriterThread->Shutdown();
   mWriterThread = nullptr;
   return NS_OK;
 }

browser_patches/firefox/juggler/protocol/BrowserHandler.js

@@ -125,13 +125,13 @@ class BrowserHandler {
   }
 
   async close() {
-    this._onclose();
     let browserWindow = Services.wm.getMostRecentWindow(
       "navigator:browser"
     );
     if (browserWindow && browserWindow.gBrowserInit) {
       await browserWindow.gBrowserInit.idleTasksFinishedPromise;
     }
+    this._onclose();
     Services.startup.quit(Ci.nsIAppStartup.eForceQuit);
   }