Revert of Reimplement AccountManagerHelper singleton instance creation

chrome/android/junit/src/org/chromium/chrome/browser/invalidation/InvalidationControllerTest.java

Index: chrome/android/junit/src/org/chromium/chrome/browser/invalidation/InvalidationControllerTest.java
diff --git a/chrome/android/junit/src/org/chromium/chrome/browser/invalidation/InvalidationControllerTest.java b/chrome/android/junit/src/org/chromium/chrome/browser/invalidation/InvalidationControllerTest.java
index ba2cc242fce53e9e2339f992863c30863ec208c0..88534f0fb725a328c3e9a232f2edc1bc00583672 100644
--- a/chrome/android/junit/src/org/chromium/chrome/browser/invalidation/InvalidationControllerTest.java
+++ b/chrome/android/junit/src/org/chromium/chrome/browser/invalidation/InvalidationControllerTest.java
@@ -12,7 +12,6 @@
 import android.content.pm.PackageInfo;
 import android.os.Bundle;
 
-import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
@@ -31,9 +30,7 @@
 import org.chromium.base.ContextUtils;
 import org.chromium.base.test.util.Feature;
 import org.chromium.chrome.browser.sync.ProfileSyncService;
-import org.chromium.components.signin.AccountManagerHelper;
 import org.chromium.components.signin.ChromeSigninController;
-import org.chromium.components.signin.SystemAccountManagerDelegate;
 import org.chromium.components.sync.AndroidSyncSettings;
 import org.chromium.components.sync.ModelType;
 import org.chromium.components.sync.ModelTypeHelper;
@@ -114,9 +111,6 @@
 
         ContextUtils.initApplicationContextForTests(mContext.getApplicationContext());
 
-        AccountManagerHelper.overrideAccountManagerHelperForTests(
-                mContext, new SystemAccountManagerDelegate());
-
         ModelTypeHelper.setTestDelegate(new ModelTypeHelper.TestDelegate() {
             @Override
             public String toNotificationType(int modelType) {
@@ -145,11 +139,6 @@
         AndroidSyncSettings.enableChromeSync(mContext);
     }
 
-    @After
-    public void tearDown() {
-        AccountManagerHelper.resetAccountManagerHelperForTests();
-    }
-
     /**
      * Verify the intent sent by InvalidationController#stop().
      */