Make CallbackHelper#waitUntilCriteria verbose during failure.

content/public/test/android/javatests/src/org/chromium/content/browser/test/util/CallbackHelper.java

Index: content/public/test/android/javatests/src/org/chromium/content/browser/test/util/CallbackHelper.java
diff --git a/content/public/test/android/javatests/src/org/chromium/content/browser/test/util/CallbackHelper.java b/content/public/test/android/javatests/src/org/chromium/content/browser/test/util/CallbackHelper.java
index e3537e847f05c9d9c43504069f75b42e01452df9..c1e91ec8a2a2eb41d4d8e849cfd6a05e574b1900 100644
--- a/content/public/test/android/javatests/src/org/chromium/content/browser/test/util/CallbackHelper.java
+++ b/content/public/test/android/javatests/src/org/chromium/content/browser/test/util/CallbackHelper.java
@@ -214,7 +214,8 @@ public class CallbackHelper {
                 mLock.wait(unit.toMillis(timeout));
                 isSatisfied = criteria.isSatisfied();
             }
-            if (!isSatisfied) throw new TimeoutException("waitUntilCriteria timed out!");
+
+            if (!isSatisfied) throw new TimeoutException(criteria.getFailureReason());
         }
     }