[S.P.] Don't draw frames of animated images that are offscreen

Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1185 matching lines @@
 
 void LayoutObject::invalidateTreeIfNeeded(const PaintInvalidationState& paintInvalidationState)
 {
     ASSERT(!needsLayout());
 
     // If we didn't need paint invalidation then our children don't need as well.
     // Skip walking down the tree as everything should be fine below us.
     if (!shouldCheckForPaintInvalidation(paintInvalidationState))
         return;
 
-    invalidatePaintIfNeeded(paintInvalidationState, paintInvalidationState.paintInvalidationContainer());
-    clearPaintInvalidationState(paintInvalidationState);
+    PaintInvalidationReason reason = invalidatePaintIfNeeded(paintInvalidationState, paintInvalidationState.paintInvalidationContainer());
+    if (reason != PaintInvalidationDelayedFull) {
+        clearPaintInvalidationState(paintInvalidationState);
+    } else {
+        // Mark this object as needing paint invalidation again in the next frame, due to the request for delayed paint invalidation.
+        setShouldDoFullPaintInvalidation(reason);
+    }
+
     invalidatePaintOfSubtreesIfNeeded(paintInvalidationState);
 }
 
 void LayoutObject::invalidatePaintOfSubtreesIfNeeded(const PaintInvalidationState& childPaintInvalidationState)
 {
     for (LayoutObject* child = slowFirstChild(); child; child = child->nextSibling()) {
         if (!child->isOutOfFlowPositioned())
             child->invalidateTreeIfNeeded(childPaintInvalidationState);
     }
 }
@@ skipping 1884 matching lines @@
     case DocumentLifecycle::InCompositingUpdate:
         return PaintInvalidationCompositingUpdate;
     default:
         return PaintInvalidationFull;
     }
 }
 
 void LayoutObject::setShouldDoFullPaintInvalidation(PaintInvalidationReason reason)
 {
     // Only full invalidation reasons are allowed.
-    ASSERT(isFullPaintInvalidationReason(reason));
+    ASSERT(isFullPaintInvalidationReason(reason) || reason == PaintInvalidationDelayedFull);
 
     if (m_bitfields.fullPaintInvalidationReason() == PaintInvalidationNone) {
         if (reason == PaintInvalidationFull)
             reason = documentLifecycleBasedPaintInvalidationReason(document().lifecycle());
         m_bitfields.setFullPaintInvalidationReason(reason);
     }
 
-    ASSERT(document().lifecycle().state() != DocumentLifecycle::InPaintInvalidation);
     frame()->page()->animator().scheduleVisualUpdate(); // In case that this is called outside of FrameView::updateLayoutAndStyleForPainting().
     markContainerChainForPaintInvalidation();
+    ASSERT(document().lifecycle().state() != DocumentLifecycle::InPaintInvalidation || reason == PaintInvalidationDelayedFull);

[esprehn, 2015/03/25 05:06:36]

This still can let in bugs with the bits, if you use a separate walk you don't
need to change any of the asserts.

[chrishtr, 2015/03/25 23:30:35]

Done.

 }
 
 void LayoutObject::setMayNeedPaintInvalidation()
 {
     if (mayNeedPaintInvalidation())
         return;
     m_bitfields.setMayNeedPaintInvalidation(true);
     // Make sure our parent is marked as needing invalidation.
     markContainerChainForPaintInvalidation();
     frame()->page()->animator().scheduleVisualUpdate(); // In case that this is called outside of FrameView::updateLayoutAndStyleForPainting().
@@ skipping 93 matching lines @@
 {
     if (object1) {
         const blink::LayoutObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
     }
 }
 
 #endif