Create NetworkQuietDetector.

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 154 matching lines @@
   return DetermineWebCachePolicy(RequestMethod::kIsNotPost,
                                  RequestType::kIsNotConditional,
                                  ResourceType::kIsNotMainResource, load_type);
 }
 
 }  // namespace
 
 FrameFetchContext::FrameFetchContext(DocumentLoader* loader, Document* document)
     : document_loader_(loader), document_(document) {
   DCHECK(GetFrame());
+  if (document)
+    network_quiet_detector_ = new NetworkQuietDetector(document);

[zhenw, 2017/06/07 17:32:56]

I think there is a question about whether NetworkQuietDetector should be scoped
to FrameFetchContext or Document.

I lean toward Document scope. First of all, this line here actually means
NetworkQuietDetector is effectively scoped to Document. And scoping to Document
means it can also be used by FMP, TTI, etc.

[lpy, 2017/06/07 18:32:45]

Done.

 }
 
 void FrameFetchContext::ProvideDocumentToContext(FetchContext& context,
                                                  Document* document) {
   DCHECK(document);
   CHECK(context.IsFrameFetchContext());
-  static_cast<FrameFetchContext&>(context).document_ = document;
+  static_cast<FrameFetchContext&>(context).SetDocument(document);
 }
 
 FrameFetchContext::~FrameFetchContext() {
   document_loader_ = nullptr;
 }
 
 LocalFrame* FrameFetchContext::FrameOfImportsController() const {
   DCHECK(GetDocument());
   HTMLImportsController* imports_controller =
       GetDocument()->ImportsController();
   DCHECK(imports_controller);
   LocalFrame* frame = imports_controller->Master()->GetFrame();
   DCHECK(frame);
   return frame;
 }
 
 RefPtr<WebTaskRunner> FrameFetchContext::GetTaskRunner() const {
   return GetFrame()->FrameScheduler()->LoadingTaskRunner();
 }
 
 Document* FrameFetchContext::GetDocument() const {
   return document_;
 }
 
+void FrameFetchContext::SetDocument(Document* document) {
+  document_ = document;
+  if (document)
+    network_quiet_detector_ = new NetworkQuietDetector(document);
+}
+
 LocalFrame* FrameFetchContext::GetFrame() const {
   if (!document_loader_)
     return FrameOfImportsController();
 
   LocalFrame* frame = document_loader_->GetFrame();
   DCHECK(frame);
   return frame;
 }
 
 LocalFrameClient* FrameFetchContext::GetLocalFrameClient() const {
@@ skipping 278 matching lines @@
     argv.push_back(Resource::ResourceTypeToString(type, fetch_initiator_name));
     argv.push_back(request.Url());
     activity_logger->LogEvent("blinkRequestResource", argv.size(), argv.data());
   }
 }
 
 void FrameFetchContext::DidLoadResource(Resource* resource) {
   if (!GetDocument())
     return;
   FirstMeaningfulPaintDetector::From(*GetDocument()).CheckNetworkStable();
+  network_quiet_detector_->CheckNetworkStable();

[zhenw, 2017/06/07 17:32:56]

I think the plan is to let FMPDetector also use this network quiet detector?

[lpy, 2017/06/07 18:32:45]

Discussed offline, updated the description to reflect the plan.

   if (resource->IsLoadEventBlockingResourceType())
     GetDocument()->CheckCompleted();
 }
 
 void FrameFetchContext::AddResourceTiming(const ResourceTimingInfo& info) {
   Document* initiator_document = GetDocument() && info.IsMainResource()
                                      ? GetDocument()->ParentDocument()
                                      : GetDocument();
   if (!initiator_document || !initiator_document->domWindow())
     return;
@@ skipping 334 matching lines @@
 
 void FrameFetchContext::Detach() {
   // This is needed to break a reference cycle in which off-heap
   // ComputedStyle is involved. See https://crbug.com/383860 for details.
   document_ = nullptr;
 }
 
 DEFINE_TRACE(FrameFetchContext) {
   visitor->Trace(document_loader_);
   visitor->Trace(document_);
+  visitor->Trace(network_quiet_detector_);
   BaseFetchContext::Trace(visitor);
 }
 
 }  // namespace blink