Fix VR Shell black screen during tests

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java b/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java
index c95b75f6ffed76f6e0aaf72d8320344f7e634660..4c5a0616f5c1b2985990655be58c4da764986ce3 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java
@@ -47,7 +47,16 @@ public class VrShellTest extends ChromeTabbedActivityTestBase {
     @Override
     protected void setUp() throws Exception {
         super.setUp();
-        mDelegate = VrShellDelegate.getInstanceForTesting();
+        // We need to run the constructor on the main/UI thread, otherwise the Choreographer
+        // acquired in the constructor is incorrect during e2e tests
+        final AtomicReference<VrShellDelegate> delegate = new AtomicReference<VrShellDelegate>();
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                delegate.set(VrShellDelegate.getInstanceForTesting());
+            }
+        });
+        mDelegate = delegate.get();
     }
 
     @Override