Reland of Reimplement AccountManagerHelper singleton instance creation

components/sync/android/javatests/src/org/chromium/components/sync/AndroidSyncSettingsTest.java

Index: components/sync/android/javatests/src/org/chromium/components/sync/AndroidSyncSettingsTest.java
diff --git a/components/sync/android/javatests/src/org/chromium/components/sync/AndroidSyncSettingsTest.java b/components/sync/android/javatests/src/org/chromium/components/sync/AndroidSyncSettingsTest.java
index 29d952b1b653721f825ee835d482e2100d2ad311..af72394ae6ebb68c922fda95d3d0cd58b5bad358 100644
--- a/components/sync/android/javatests/src/org/chromium/components/sync/AndroidSyncSettingsTest.java
+++ b/components/sync/android/javatests/src/org/chromium/components/sync/AndroidSyncSettingsTest.java
@@ -126,6 +126,12 @@ public class AndroidSyncSettingsTest extends InstrumentationTestCase {
         return account;
     }
 
+    @Override
+    protected void tearDown() throws Exception {
+        AccountManagerHelper.resetAccountManagerHelperForTests();
+        super.tearDown();
+    }
+
     private void enableChromeSyncOnUiThread() {
         ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override