feat: add exit code to render-process-gone details (#27580)

docs/api/app.md

@@ -406,6 +406,9 @@ Returns:
     * `oom` - Process ran out of memory
     * `launch-failed` - Process never successfully launched
     * `integrity-failure` - Windows code integrity checks failed
+  * `exitCode` Integer - The exit code of the process, unless `reason` is
+    `launch-failed`, in which case `exitCode` will be a platform-specific
+    launch failure error code.
 
 Emitted when the renderer process unexpectedly disappears.  This is normally
 because it was crashed or killed.

docs/api/web-contents.md

@@ -403,6 +403,9 @@ Returns:
     * `oom` - Process ran out of memory
     * `launch-failed` - Process never successfully launched
     * `integrity-failure` - Windows code integrity checks failed
+  * `exitCode` Integer - The exit code of the process, unless `reason` is
+    `launch-failed`, in which case `exitCode` will be a platform-specific
+    launch failure error code.
 
 Emitted when the renderer process unexpectedly disappears.  This is normally
 because it was crashed or killed.

shell/browser/api/electron_api_web_contents.cc

@@ -1396,6 +1396,7 @@ void WebContents::RenderProcessGone(base::TerminationStatus status) {
   v8::HandleScope handle_scope(isolate);
   gin_helper::Dictionary details = gin_helper::Dictionary::CreateEmpty(isolate);
   details.Set("reason", status);
+  details.Set("exitCode", web_contents()->GetCrashedErrorCode());
   Emit("render-process-gone", details);
 }