Fix Java PersonalDataManagerTest flake.

chrome/android/java/src/org/chromium/chrome/browser/autofill/PersonalDataManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/autofill/PersonalDataManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/autofill/PersonalDataManager.java b/chrome/android/java/src/org/chromium/chrome/browser/autofill/PersonalDataManager.java
index 2c0f3063174b26c401e401f0b788f86e0c93d486..059cee3757afa2eca75e2c541bc7800c3fc1f238 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/autofill/PersonalDataManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/autofill/PersonalDataManager.java
@@ -498,10 +498,11 @@ public class PersonalDataManager {
     /**
      * Registers a PersonalDataManagerObserver on the native side.
      */
-    public void registerDataObserver(PersonalDataManagerObserver observer) {
+    public boolean registerDataObserver(PersonalDataManagerObserver observer) {
         ThreadUtils.assertOnUiThread();
         assert !mDataObservers.contains(observer);
         mDataObservers.add(observer);
+        return nativeIsDataLoaded(mPersonalDataManagerAndroid);
     }
 
     /**
@@ -754,6 +755,7 @@ public class PersonalDataManager {
     }
 
     private native long nativeInit();
+    private native boolean nativeIsDataLoaded(long nativePersonalDataManagerAndroid);
     private native String[] nativeGetProfileGUIDsForSettings(long nativePersonalDataManagerAndroid);
     private native String[] nativeGetProfileGUIDsToSuggest(long nativePersonalDataManagerAndroid);
     private native String[] nativeGetProfileLabelsForSettings(