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

Source/core/layout/LayoutObject.cpp

Index: Source/core/layout/LayoutObject.cpp
diff --git a/Source/core/layout/LayoutObject.cpp b/Source/core/layout/LayoutObject.cpp
index d4348ce568893542bdb893da760d63d528ab85b1..1a06ec6756a7ff22568b75c1e7b849da58243c45 100644
--- a/Source/core/layout/LayoutObject.cpp
+++ b/Source/core/layout/LayoutObject.cpp
@@ -1200,8 +1200,14 @@ void LayoutObject::invalidateTreeIfNeeded(const PaintInvalidationState& paintInv
     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);
 }
 
@@ -3105,8 +3111,10 @@ static PaintInvalidationReason documentLifecycleBasedPaintInvalidationReason(con
 
 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)
@@ -3114,9 +3122,9 @@ void LayoutObject::setShouldDoFullPaintInvalidation(PaintInvalidationReason reas
         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);

[chrishtr, 2015/03/20 16:58:54]

I also restored the asserts in this method to avoid broken call sites elsewhere.

 }
 
 void LayoutObject::setMayNeedPaintInvalidation()