Add way to get native VR UI information from Java

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

Index: chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrUtils.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrUtils.java b/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrUtils.java
index 7e5797911605c7419a338e00258528b5395a13ea..60b48458b57916ffe332b67a420f16a0f9478673 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrUtils.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrUtils.java
@@ -15,10 +15,12 @@ import android.nfc.NfcAdapter;
 import org.chromium.base.ThreadUtils;
 import org.chromium.content.browser.test.util.Criteria;
 import org.chromium.content.browser.test.util.CriteriaHelper;
+import org.chromium.content_public.browser.WebContents;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.concurrent.Callable;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * Class containing static functions and constants that are useful for VR
@@ -122,4 +124,21 @@ public class VrUtils {
             }
         }), timeout, POLL_CHECK_INTERVAL_SHORT_MS);
     }
+
+    /**
+     * Tries to get the HTML UI WebContents from VrShell.
+     * @param timeout The timeout for getting the WebContents in milliseconds
+     * @return The WebContents for the HTML UI.
+     */
+    public static WebContents getVrShellUiContents(final int timeout) {
+        final AtomicReference<VrShellImpl> vrShell = new AtomicReference<VrShellImpl>();
+        CriteriaHelper.pollUiThread(Criteria.equals(true, new Callable<Boolean>() {
+            @Override
+            public Boolean call() {
+                vrShell.set((VrShellImpl) VrShellDelegate.getVrShellForTesting());
+                return vrShell.get() != null && vrShell.get().getUiContentsForTesting() != null;
+            }
+        }), timeout, POLL_CHECK_INTERVAL_LONG_MS);
+        return vrShell.get().getUiContentsForTesting();
+    }
 }