Measure time spent in SharedPrefs-loading StrictMode violations.

chrome/android/java/src/org/chromium/chrome/browser/webapps/ActivityAssigner.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.webapps;
 
 import android.content.Context;
 import android.content.SharedPreferences;
+import android.os.SystemClock;
 import android.util.Log;
 
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.VisibleForTesting;
+import org.chromium.base.metrics.RecordHistogram;
 
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Manages a rotating LRU buffer of WebappActivities to assign webapps to.
  *
  * In order to accommodate a limited number of WebappActivities with a potentially unlimited number
  * of webapps, we have to rotate the available WebappActivities between the webapps we start up.
  * Activities are reused in order of when they were last used, with the least recently used
  * ones culled first.
  *
  * It is impossible to know whether Tasks have been removed from the Recent Task list without the
@@ skipping 179 matching lines @@
         // Activity has already been assigned.
         Set<Integer> availableWebapps = new HashSet<Integer>();
         for (int i = 0; i < NUM_WEBAPP_ACTIVITIES; ++i) {
             availableWebapps.add(i);
         }
 
         // Restore any entries that were previously saved.  If it seems that the preferences have
         // been corrupted somehow, just discard the whole map.
         SharedPreferences prefs = mContext.getSharedPreferences(PREF_PACKAGE, Context.MODE_PRIVATE);
         try {
+            long time = SystemClock.elapsedRealtime();
             final int numSavedEntries = prefs.getInt(PREF_NUM_SAVED_ENTRIES, 0);
+            try {
+                RecordHistogram.recordTimesHistogram("Android.StrictMode.WebappSharedPrefs",
+                        SystemClock.elapsedRealtime() - time, TimeUnit.MILLISECONDS);
+            } catch (UnsatisfiedLinkError error) {
+                // Intentionally ignored - it's ok to miss recording the metric occasionally.
+            }
             if (numSavedEntries <= NUM_WEBAPP_ACTIVITIES) {
                 for (int i = 0; i < numSavedEntries; ++i) {
                     String currentActivityIndexPref = PREF_ACTIVITY_INDEX + i;
                     String currentWebappIdPref = PREF_WEBAPP_ID + i;
 
                     int activityIndex = prefs.getInt(currentActivityIndexPref, i);
                     String webappId = prefs.getString(currentWebappIdPref, null);
                     ActivityEntry entry = new ActivityEntry(activityIndex, webappId);
 
                     if (availableWebapps.remove(entry.mActivityIndex)) {
@@ skipping 37 matching lines @@
         editor.putInt(PREF_NUM_SAVED_ENTRIES, mActivityList.size());
         for (int i = 0; i < mActivityList.size(); ++i) {
             String currentActivityIndexPref = PREF_ACTIVITY_INDEX + i;
             String currentWebappIdPref = PREF_WEBAPP_ID + i;
             editor.putInt(currentActivityIndexPref, mActivityList.get(i).mActivityIndex);
             editor.putString(currentWebappIdPref, mActivityList.get(i).mWebappId);
         }
         editor.apply();
     }
 }