Move Cronet metrics-related classes into their own files

components/cronet/android/api/src/org/chromium/net/RequestFinishedInfo.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;
+
+import android.support.annotation.Nullable;
+
+import java.util.Collection;
+
+/**
+ * Information about a finished request. Passed to {@link RequestFinishedListener}.
+ *
+ * {@hide} as it's a prototype.
+ */
+public final class RequestFinishedInfo {

[xunjieli, 2016/08/01 20:40:05]

I like the new name! What do you think about moving RequestFinishedListener here
as a nested class? Maybe we can do something like RequestFinishedInfo.Listener?

If UrlRequestMetrics is only used in RequestFinishedInfo, can we also nest it
here? and call it metrics?

+    private final String mUrl;
+    private final Collection<Object> mAnnotations;
+    private final UrlRequestMetrics mMetrics;
+    @Nullable
+    private final UrlResponseInfo mResponseInfo;
+
+    /**
+     * @hide only used by internal implementation.
+     */
+    public RequestFinishedInfo(String url, Collection<Object> annotations,
+            UrlRequestMetrics metrics, @Nullable UrlResponseInfo responseInfo) {
+        mUrl = url;
+        mAnnotations = annotations;
+        mMetrics = metrics;
+        mResponseInfo = responseInfo;
+    }
+
+    /** Returns the request's original URL. */
+    public String getUrl() {
+        return mUrl;
+    }
+
+    /** Returns the objects that the caller has supplied when initiating the request. */
+    public Collection<Object> getAnnotations() {
+        return mAnnotations;
+    }
+
+    // TODO(klm): Collect and return a chain of Metrics objects for redirect responses.
+    /**
+     * Returns metrics collected for this request.
+     *
+     * <p>The reported times and bytes account for all redirects, i.e.
+     * the TTFB is from the start of the original request to the ultimate response headers,
+     * the TTLB is from the start of the original request to the end of the ultimate response,
+     * the received byte count is for all redirects and the ultimate response combined.
+     * These cumulative metric definitions are debatable, but are chosen to make sense
+     * for user-facing latency analysis.
+     *
+     * <p>Must call {@link #enableNetworkQualityEstimator} to enable request metrics collection.
+     * @return metrics collected for this request.
+     */
+    public UrlRequestMetrics getMetrics() {
+        return mMetrics;
+    }
+
+    /**
+     * Returns a {@link UrlResponseInfo} for the request, if its response had started.
+     * @return {@link UrlResponseInfo} for the request, if its response had started.
+     */
+    @Nullable
+    public UrlResponseInfo getResponseInfo() {
+        return mResponseInfo;
+    }
+}