FrameView: Don't throttle display:none frames

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

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 530e1224f1a96424eb13c66f5798ccacf1afc45d..546a64a6a084e5a0526d54d8bdb954fa5b0a55a9 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -4642,6 +4642,13 @@ void FrameView::updateViewportIntersectionsForSubtree(
         ->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())
@@ -4662,9 +4669,11 @@ void FrameView::updateRenderThrottlingStatus(bool hidden,
   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();