Precache should cancel when there is user traffic

chrome/browser/precache/precache_util.cc

Index: chrome/browser/precache/precache_util.cc
diff --git a/chrome/browser/precache/precache_util.cc b/chrome/browser/precache/precache_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..80ec4a1e9756d8814a4ba4d9ed45304b4940e112
--- /dev/null
+++ b/chrome/browser/precache/precache_util.cc
@@ -0,0 +1,72 @@
+// 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.
+
+#include "chrome/browser/precache/precache_util.h"
+
+#include "base/time/time.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/precache/precache_manager_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "components/data_use_measurement/content/data_use_measurement.h"
+#include "components/precache/content/precache_manager.h"
+#include "content/public/browser/browser_thread.h"
+#include "net/url_request/url_request.h"
+#include "url/gurl.h"
+
+namespace {
+
+void UpdatePrecacheMetricsAndStateOnUIThread(const GURL& url,
+                                             const GURL& referrer,
+                                             base::TimeDelta latency,
+                                             const base::Time& fetch_time,
+                                             int64_t size,
+                                             bool was_cached,
+                                             bool is_user_traffic,
+                                             void* profile_id) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  if (!g_browser_process->profile_manager()->IsValidProfile(profile_id))
+    return;
+  Profile* profile = reinterpret_cast<Profile*>(profile_id);
+
+  precache::PrecacheManager* precache_manager =
+      precache::PrecacheManagerFactory::GetForBrowserContext(profile);
+  // |precache_manager| could be NULL if the profile is off the record.
+  if (!precache_manager || !precache_manager->IsPrecachingAllowed())
+    return;
+
+  precache_manager->UpdatePrecacheMetricsAndState(
+      url, referrer, latency, fetch_time, size, was_cached, is_user_traffic);
+}
+
+}  // namespace
+
+namespace precache {
+
+// TODO(rajendrant): Add unittests for this function.
+void UpdatePrecacheMetricsAndState(const net::URLRequest* request,
+                                   void* profile_id) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+
+  // For better accuracy, we use the actual bytes read instead of the length
+  // specified with the Content-Length header, which may be inaccurate,
+  // or missing, as is the case with chunked encoding.
+  int64_t received_content_length = request->received_response_content_length();
+  base::TimeDelta latency = base::TimeTicks::Now() - request->creation_time();
+
+  // Record precache metrics when a fetch is completed successfully, if
+  // precaching is allowed.
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(
+          &UpdatePrecacheMetricsAndStateOnUIThread, request->url(),
+          GURL(request->referrer()), latency, base::Time::Now(),
+          received_content_length, request->was_cached(),
+          data_use_measurement::DataUseMeasurement::IsUserInitiatedRequest(
+              request),
+          profile_id));
+}
+
+}  // namespace precache