Add prefetch UMA metrics.

net/url_request/test_url_fetcher_factory.cc

 // Copyright (c) 2012 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.
 
 #include "net/url_request/test_url_fetcher_factory.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 338 matching lines @@
     case URLRequestStatus::CANCELED:
       error = ERR_ABORTED;
       break;
     case URLRequestStatus::FAILED:
       error = ERR_FAILED;
       break;
   }
   set_status(URLRequestStatus(status, error));
   set_response_code(response_code);
   SetResponseString(response_data);
+  response_bytes_ = response_data.size();
 }
 
 FakeURLFetcher::~FakeURLFetcher() {}
 
 void FakeURLFetcher::Start() {
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE,
       base::Bind(&FakeURLFetcher::RunDelegate, weak_factory_.GetWeakPtr()));
 }
 
 void FakeURLFetcher::RunDelegate() {
-  delegate()->OnURLFetchComplete(this);
+  // OnURLFetchDownloadProgress may delete this URLFetcher. We keep track of
+  // this with a weak pointer, and only call OnURLFetchComplete if this still
+  // exists.
+  auto weak_this = weak_factory_.GetWeakPtr();
+  delegate()->OnURLFetchDownloadProgress(this, response_bytes_,
+                                         response_bytes_);
+  if (weak_this.get())
+    delegate()->OnURLFetchComplete(this);
 }
 
 const GURL& FakeURLFetcher::GetURL() const {
   return TestURLFetcher::GetOriginalURL();
 }
 
 FakeURLFetcherFactory::FakeURLFetcherFactory(
     URLFetcherFactory* default_factory)
     : ScopedURLFetcherFactory(this),
       creator_(base::Bind(&DefaultFakeURLFetcherCreator)),
@@ skipping 65 matching lines @@
 
 scoped_ptr<URLFetcher> URLFetcherImplFactory::CreateURLFetcher(
     int id,
     const GURL& url,
     URLFetcher::RequestType request_type,
     URLFetcherDelegate* d) {
   return scoped_ptr<URLFetcher>(new URLFetcherImpl(url, request_type, d));
 }
 
 }  // namespace net