Create NetworkQuietDetector.

third_party/WebKit/Source/core/loader/NetworkQuietDetector.cpp

Index: third_party/WebKit/Source/core/loader/NetworkQuietDetector.cpp
diff --git a/third_party/WebKit/Source/core/loader/NetworkQuietDetector.cpp b/third_party/WebKit/Source/core/loader/NetworkQuietDetector.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..729d3629a281b4aa4a66eabdd491c48ab8ec15f1
--- /dev/null
+++ b/third_party/WebKit/Source/core/loader/NetworkQuietDetector.cpp
@@ -0,0 +1,65 @@
+// Copyright 2017 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 "core/loader/NetworkQuietDetector.h"
+
+#include "core/dom/Document.h"
+#include "core/dom/TaskRunnerHelper.h"
+#include "core/frame/LocalFrame.h"
+#include "core/loader/FrameFetchContext.h"
+#include "platform/instrumentation/resource_coordinator/FrameResourceCoordinator.h"
+#include "platform/loader/fetch/ResourceFetcher.h"
+
+namespace blink {
+
+NetworkQuietDetector::NetworkQuietDetector(Document* document)
+    : document_(document),
+      network2_quiet_timer_(
+          TaskRunnerHelper::Get(TaskType::kUnspecedTimer, document),
+          this,
+          &NetworkQuietDetector::Network2QuietTimerFired) {}
+
+int NetworkQuietDetector::ActiveConnections() {
+  ResourceFetcher* fetcher = document_->Fetcher();
+  return fetcher->BlockingRequestCount() + fetcher->NonblockingRequestCount();
+}
+
+// This function is called when the number of active connections is decreased.
+void NetworkQuietDetector::CheckNetworkStable() {
+  if (!document_->HasFinishedParsing())
+    return;
+
+  SetNetworkQuietTimers(ActiveConnections());
+}
+
+void NetworkQuietDetector::SetNetworkQuietTimers(int active_connections) {
+  if (network2_quiet_reached_ || active_connections > 2)
+    return;
+
+  // If activeConnections < 2 and the timer is already running, current
+  // 2-quiet window continues; the timer shouldn't be restarted.
+  if (active_connections == 2 || !network2_quiet_timer_.IsActive()) {
+    network2_quiet_timer_.StartOneShot(kNetwork2QuietWindowSeconds,
+                                       BLINK_FROM_HERE);
+  }
+}
+
+void NetworkQuietDetector::Network2QuietTimerFired(TimerBase*) {
+  if (!document_ || !document_->GetFrame() || network2_quiet_reached_ ||
+      ActiveConnections() > 2)
+    return;
+  network2_quiet_reached_ = true;
+  auto frame_resource_coordinator =
+      document_->GetFrame()->GetFrameResourceCoordinator();
+  if (frame_resource_coordinator) {
+    frame_resource_coordinator->SendEvent(
+        resource_coordinator::mojom::EventType::kOnLocalFrameNetworkIdle);
+  }
+}
+
+DEFINE_TRACE(NetworkQuietDetector) {
+  visitor->Trace(document_);
+}
+
+}  // namespace blink