FrameView: Don't throttle display:none frames

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 4624 matching lines @@
     return;
 
   // Notify javascript IntersectionObservers
   if (targetState == DocumentLifecycle::PaintClean &&
       frame().document()->intersectionObserverController())
     frame()
         .document()
         ->intersectionObserverController()
         ->computeTrackedIntersectionObservations();
 
+  // Don't throttle display:none frames (see updateRenderThrottlingStatus).
+  HTMLFrameOwnerElement* ownerElement = m_frame->deprecatedLocalOwner();
+  if (m_hiddenForThrottling && ownerElement && !ownerElement->layoutObject()) {
+    updateRenderThrottlingStatus(m_hiddenForThrottling, m_subtreeThrottled);

[esprehn, 2017/02/14 00:05:21]

This introduces an entire frame tree walk down here, which is redundant with the
frame tree walk that's happening on the following lines.

[Sami, 2017/02/21 12:34:03]

Well spotted -- fix here: https://codereview.chromium.org/2706193003/

+    DCHECK(!canThrottleRendering());
+  }
+
   for (Frame* child = m_frame->tree().firstChild(); child;
        child = child->tree().nextSibling()) {
     if (!child->isLocalFrame())
       continue;
     if (FrameView* view = toLocalFrame(child)->view())
       view->updateViewportIntersectionsForSubtree(targetState);
   }
 }
 
 void FrameView::updateRenderThrottlingStatusForTesting() {
   m_visibilityObserver->deliverObservationsForTesting();
 }
 
 void FrameView::updateRenderThrottlingStatus(bool hidden,
                                              bool subtreeThrottled) {
   TRACE_EVENT0("blink", "FrameView::updateRenderThrottlingStatus");
   DCHECK(!isInPerformLayout());
   DCHECK(!m_frame->document() || !m_frame->document()->inStyleRecalc());
   bool wasThrottled = canThrottleRendering();
 
-  // Note that we disallow throttling of 0x0 frames because some sites use
-  // them to drive UI logic.
-  m_hiddenForThrottling = hidden && !frameRect().isEmpty();
+  // Note that we disallow throttling of 0x0 and display:none frames because
+  // some sites use them to drive UI logic.
+  HTMLFrameOwnerElement* ownerElement = m_frame->deprecatedLocalOwner();
+  m_hiddenForThrottling = hidden && !frameRect().isEmpty() &&
+                          (ownerElement && ownerElement->layoutObject());
   m_subtreeThrottled = subtreeThrottled;
 
   bool isThrottled = canThrottleRendering();
   bool becameUnthrottled = wasThrottled && !isThrottled;
 
   // If this FrameView became unthrottled or throttled, we must make sure all
   // its children are notified synchronously. Otherwise we 1) might attempt to
   // paint one of the children with an out-of-date layout before
   // |updateRenderThrottlingStatus| has made it throttled or 2) fail to
   // unthrottle a child whose parent is unthrottled by a later notification.
@@ skipping 383 matching lines @@
     std::unique_ptr<CompositorAnimationTimeline> timeline) {
   m_animationTimeline = std::move(timeline);
 }
 
 void FrameView::setAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   m_animationHost = std::move(host);
 }
 
 }  // namespace blink