Deferred frame loading stats v2

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 4377 matching lines @@
     parent->m_needsUpdateViewportIntersectionInSubtree = true;
 }
 
 void FrameView::updateViewportIntersectionIfNeeded() {
   if (!m_needsUpdateViewportIntersection)
     return;
   m_needsUpdateViewportIntersection = false;
   m_viewportIntersectionValid = true;
   FrameView* parent = parentFrameView();
   if (!parent) {
+    if (HTMLFrameOwnerElement* element = frame().deprecatedLocalOwner()) {
+      if (!element->layoutObject())
+        frame().document()->wouldLoadBecause(WouldLoadDisplayNone);
+    }
+    frame().document()->wouldLoadBecause(WouldLoadOutOfProcess);

[dcheng, 2016/10/08 00:46:22]

Should this be in an else?

[dgrogan, 2016/10/13 01:06:22]

It was ok without one because of the check in Document::wouldLoadBecause that
only records to UMA on the first call. But it's clearer with the "else" so
changed.

     m_viewportIntersection = frameRect();
     return;
   }
   ASSERT(!parent->m_needsUpdateViewportIntersection);
 
+  bool parentLoaded = parent->frame().document()->wouldLoadReason() != Created;

[dcheng, 2016/10/08 00:46:22]

Maybe add a comment here: it'll help me understand why we care about the parent
frame's load reason being something other than created. I guess it's because we
want to only "chain" down the reasons once the parent frame has proceeded past
the Created state, but an explicit comment to that effect might be good.

[dgrogan, 2016/10/13 01:06:22]

Comment added. I think we're saying the same thing but let me know if it's still
not clear. Also, changed the != to > for easier understanding.

+  if (parentLoaded) {
+    if (frameRect().isEmpty())
+      frame().document()->wouldLoadBecause(WouldLoadZeroByZero);
+    else if (frameRect().maxY() < 0)
+      frame().document()->wouldLoadBecause(WouldLoadAbove);
+    else if (frameRect().maxX() < 0)
+      frame().document()->wouldLoadBecause(WouldLoadLeft);
+  }
+
   // If our parent is hidden, then we are too.
   if (parent->m_viewportIntersection.isEmpty()) {
     m_viewportIntersection = parent->m_viewportIntersection;
     return;
   }
 
   // Transform our bounds into the root frame's content coordinate space,
   // making sure we have valid layout data in our parent document. If our
   // parent is throttled, we'll use possible stale layout information and
   // rely on the fact that another lifecycle update will be scheduled once
   // our parent becomes unthrottled.
   ASSERT(parent->lifecycle().state() >= DocumentLifecycle::LayoutClean ||
          parent->shouldThrottleRendering());
   m_viewportIntersection = parent->contentsToRootFrame(frameRect());
 
   // TODO(skyostil): Expand the viewport to make it less likely to see stale
   // content while scrolling.
   IntRect viewport = parent->m_viewportIntersection;
   m_viewportIntersection.intersect(viewport);
+
+  if (parentLoaded && !m_viewportIntersection.isEmpty())
+    frame().document()->wouldLoadBecause(WouldLoadVisible);
 }
 
 void FrameView::updateViewportIntersectionsForSubtree(
     DocumentLifecycle::LifecycleState targetState) {
   bool hadValidIntersection = m_viewportIntersectionValid;
   bool hadEmptyIntersection = m_viewportIntersection.isEmpty();
   updateViewportIntersectionIfNeeded();
 
   // Notify javascript IntersectionObservers
   if (targetState == DocumentLifecycle::PaintClean &&
@@ skipping 65 matching lines @@
 
 void FrameView::notifyRenderThrottlingObservers() {
   TRACE_EVENT0("blink", "FrameView::notifyRenderThrottlingObservers");
   DCHECK(!isInPerformLayout());
   DCHECK(frame().document());
   DCHECK(!frame().document()->inStyleRecalc());
   bool wasThrottled = canThrottleRendering();
 
   updateThrottlingStatus();
 
-  frame().document()->onVisibilityMaybeChanged(!m_hiddenForThrottling);
-
   bool becameThrottled = !wasThrottled && canThrottleRendering();
   bool becameUnthrottled = wasThrottled && !canThrottleRendering();
   ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator();
   if (becameThrottled) {
     // If this FrameView became throttled, we must make sure all of its
     // children become throttled at the same time. Otherwise we might
     // attempt to paint one of the children with an out-of-date layout
     // before |notifyRenderThrottlingObservers| has made it throttled.
     forAllNonThrottledFrameViews([](FrameView& frameView) {
       frameView.m_subtreeThrottled = true;
@@ skipping 38 matching lines @@
 }
 
 bool FrameView::canThrottleRendering() const {
   if (!RuntimeEnabledFeatures::renderingPipelineThrottlingEnabled())
     return false;
   return m_subtreeThrottled ||
          (m_hiddenForThrottling && m_crossOriginForThrottling);
 }
 
 }  // namespace blink