From 9cfc67ef57fb2cdcbf0fcce1b48aad328f5b5c2d Mon Sep 17 00:00:00 2001
From: Adam Barth <github@adambarth.com>
Date: Thu, 4 May 2017 21:30:39 -0700
Subject: [PATCH] Retrieve the last error from the proper thread (#3649)

Previously, the last error was a global static. Now it is a thread-specific
value, which means we need to visit the UI thread to read the value.
---
 shell/platform/linux/main_linux.cc | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/shell/platform/linux/main_linux.cc b/shell/platform/linux/main_linux.cc
index 25750fa6fe6cd..cfd08ab243382 100644
--- a/shell/platform/linux/main_linux.cc
+++ b/shell/platform/linux/main_linux.cc
@@ -102,8 +102,14 @@ void RunNonInteractive(ftl::CommandLine initial_command_line,
       test_runner.platform_view().engine().GetLoadScriptError();
   if (error == tonic::kNoError)
     error = task_observer.last_error();
-  if (error == tonic::kNoError)
-    error = tonic::DartMicrotaskQueue::GetForCurrentThread()->GetLastError();
+  if (error == tonic::kNoError) {
+    ftl::AutoResetWaitableEvent latch;
+    blink::Threads::UI()->PostTask([&error, &latch] {
+      error = tonic::DartMicrotaskQueue::GetForCurrentThread()->GetLastError();
+      latch.Signal();
+    });
+    latch.Wait();
+  }
 
   // The script has completed and the engine may not be in a clean state,
   // so just stop the process.