Implement timing metrics for UrlRequest

components/cronet/android/java/src/org/chromium/net/impl/CronetMetrics.java

 // Copyright 2016 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.net.impl;
 
 import android.support.annotation.Nullable;
 
 import org.chromium.base.VisibleForTesting;
 import org.chromium.net.RequestFinishedInfo;
@@ skipping 81 matching lines @@
             long sendingEndMs, long pushStartMs, long pushEndMs, long responseStartMs,
             long responseEndMs, boolean socketReused, long sentBytesCount,
             long receivedBytesCount) {
         // Check that no end times are before corresponding start times,
         // or exist when start time doesn't.
         assert checkOrder(dnsStartMs, dnsEndMs);
         assert checkOrder(connectStartMs, connectEndMs);
         assert checkOrder(sslStartMs, sslEndMs);
         assert checkOrder(sendingStartMs, sendingEndMs);
         assert checkOrder(pushStartMs, pushEndMs);
-        assert checkOrder(responseStartMs, responseEndMs);
+        // responseEnd always exists, so just check that it's after start
+        assert responseEndMs >= responseStartMs;
         // Spot-check some of the other orderings
         assert dnsStartMs >= requestStartMs || dnsStartMs == -1;
         assert sendingStartMs >= requestStartMs || sendingStartMs == -1;
         assert sslStartMs >= connectStartMs || sslStartMs == -1;
         assert responseStartMs >= sendingStartMs || responseStartMs == -1;
         mRequestStartMs = requestStartMs;
         mDnsStartMs = dnsStartMs;
         mDnsEndMs = dnsEndMs;
         mConnectStartMs = connectStartMs;
         mConnectEndMs = connectEndMs;
@@ skipping 105 matching lines @@
     @Nullable
     public Long getSentBytesCount() {
         return mSentBytesCount;
     }
 
     @Nullable
     public Long getReceivedBytesCount() {
         return mReceivedBytesCount;
     }
 }