Update to newer Android Lint and suppress new Lint errors

chrome/android/java/src/org/chromium/chrome/browser/precache/PrecacheController.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.chrome.browser.precache;
 
+import android.annotation.SuppressLint;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.SharedPreferences;
 import android.net.ConnectivityManager;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.PowerManager;
 import android.os.PowerManager.WakeLock;
@@ skipping 57 matching lines @@
             Collections.unmodifiableSet(new HashSet<Integer>(Arrays.asList(ModelType.SESSIONS)));
 
     private static final String PREF_PRECACHE_PERIODIC_TASK_START_TIME_MS =
             "precache.periodic_task_start_time_ms";
 
     /**
      * Singleton instance of the PrecacheController. PrecacheController is a
      * singleton so that there is a single handle by which to determine if
      * precaching is underway, and to cancel it if necessary.
      */
+    @SuppressLint("StaticFieldLeak")
     private static PrecacheController sInstance;
 
     /**
      * The default task scheduler. Overridden for tests.
      */
     private static PrecacheTaskScheduler sTaskScheduler = new PrecacheTaskScheduler();
 
     /**
      * Listener for syncservice backend.
      */
@@ skipping 467 matching lines @@
 
     private void recordBatteryLevelAtEnd() {
         int delta_percentage = mDeviceState.getCurrentBatteryPercentage(mAppContext)
                 - mDeviceState.getSavedBatteryPercentage();
         if (delta_percentage >= 0) {
             RecordHistogram.recordPercentageHistogram(
                     "Precache.BatteryPercentageDiff.End", delta_percentage);
         }
     }
 }