Update to newer Android Lint and suppress new Lint errors

content/public/android/java/src/org/chromium/content/browser/BackgroundSyncNetworkObserver.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.content.browser;
 
 import android.Manifest;
+import android.annotation.SuppressLint;
 import android.content.pm.PackageManager;
 import android.os.Process;
 
 import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.annotations.NativeClassQualifiedName;
 import org.chromium.base.metrics.RecordHistogram;
@@ skipping 15 matching lines @@
  *
  * This class lives on the main thread.
  */
 @JNINamespace("content")
 class BackgroundSyncNetworkObserver implements NetworkChangeNotifierAutoDetect.Observer {
     private static final String TAG = "cr_BgSyncNetObserver";
 
     private NetworkChangeNotifierAutoDetect mNotifier;
 
     // The singleton instance.
+    @SuppressLint("StaticFieldLeak")
     private static BackgroundSyncNetworkObserver sInstance;
 
     // List of native observers. These are each called when the network state changes.
     private List<Long> mNativePtrs;
 
     private BackgroundSyncNetworkObserver() {
         ThreadUtils.assertOnUiThread();
         mNativePtrs = new ArrayList<Long>();
     }
 
@@ skipping 61 matching lines @@
     @Override
     public void onNetworkSoonToDisconnect(long netId) {}
     @Override
     public void onNetworkDisconnect(long netId) {}
     @Override
     public void purgeActiveNetworkList(long[] activeNetIds) {}
 
     @NativeClassQualifiedName("BackgroundSyncNetworkObserverAndroid::Observer")
     private native void nativeNotifyConnectionTypeChanged(long nativePtr, int newConnectionType);
 }