Create NetworkQuietDetector.

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

Index: third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp b/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
index 92e76b7a0daddc290f6d349084370051bb31f948..4b15b5e5d03f2d7348a0447acbe406ead1bbfbd1 100644
--- a/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
@@ -172,13 +172,15 @@ WebCachePolicy DetermineFrameWebCachePolicy(Frame* frame,
 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() {
@@ -203,6 +205,12 @@ 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();
@@ -501,6 +509,7 @@ 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();
 }
@@ -855,6 +864,7 @@ void FrameFetchContext::Detach() {
 DEFINE_TRACE(FrameFetchContext) {
   visitor->Trace(document_loader_);
   visitor->Trace(document_);
+  visitor->Trace(network_quiet_detector_);
   BaseFetchContext::Trace(visitor);
 }