Use recomputed interest rect only if it changed enough

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 2173 matching lines @@
     TransformRecorder transformRecorder(context, *scrollbar, AffineTransform::translation(-scrollbarRect.x(), -scrollbarRect.y()));
     IntRect transformedClip = clip;
     transformedClip.moveBy(scrollbarRect.location());
     scrollbar->paint(&context, CullRect(transformedClip));
 }
 
 // The following should be kept in sync with the code computing potential_new_recorded_viewport in
 // cc::DisplayListRecordingSource::UpdateAndExpandInvalidation() before we keep only one copy of the algorithm.
 static const int kPixelDistanceToRecord = 4000;
 
-IntRect CompositedLayerMapping::computeInterestRect(const GraphicsLayer* graphicsLayer, LayoutObject* owningLayoutObject)
+IntRect CompositedLayerMapping::recomputeInterestRect(const GraphicsLayer* graphicsLayer, LayoutObject* owningLayoutObject)
 {
     FloatRect graphicsLayerBounds(FloatPoint(), graphicsLayer->size());
 
     // Start with the bounds of the graphics layer in the space of the owning LayoutObject.
     FloatRect graphicsLayerBoundsInObjectSpace(graphicsLayerBounds);
     graphicsLayerBoundsInObjectSpace.move(graphicsLayer->offsetFromLayoutObject());
 
     // Now map the bounds to its visible content rect in screen space, including applying clips along the way.
     LayoutRect visibleContentRect(graphicsLayerBoundsInObjectSpace);
     LayoutView* rootView = owningLayoutObject->view();
@@ skipping 44 matching lines @@
     if (newInterestRect.y() == 0 && previousInterestRect.y() != 0)
         return true;
     if (newInterestRect.maxX() == layerSize.width() && previousInterestRect.maxX() != layerSize.width())
         return true;
     if (newInterestRect.maxY() == layerSize.height() && previousInterestRect.maxY() != layerSize.height())
         return true;
 
     return false;
 }
 
-void CompositedLayerMapping::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& context, GraphicsLayerPaintingPhase graphicsLayerPaintingPhase, const IntRect* interestRect) const
+IntRect CompositedLayerMapping::computeInterestRect(const GraphicsLayer* graphicsLayer, const IntRect& previousInterestRect) const
 {
-    IntRect defaultInterestRect;
-    if (RuntimeEnabledFeatures::slimmingPaintSynchronizedPaintingEnabled()) {
-        if (!interestRect) {
-            if (graphicsLayer == m_graphicsLayer || graphicsLayer == m_squashingLayer)
-                defaultInterestRect = computeInterestRect(graphicsLayer, m_owningLayer.layoutObject());
-            else
-                defaultInterestRect = enclosingIntRect(FloatRect(FloatPoint(), graphicsLayer->size()));
-            interestRect = &defaultInterestRect;
-        }
+    if (graphicsLayer != m_graphicsLayer && graphicsLayer != m_squashingLayer)
+        return IntRect(IntPoint(), expandedIntSize(graphicsLayer->size()));
 
-        if (!m_owningLayer.needsRepaint()
-            && !context.paintController().cacheIsEmpty()
-            && !interestRectChangedEnoughToRepaint(m_previousPaintInterestRect, *interestRect, expandedIntSize(graphicsLayer->size()))) {
-            context.paintController().createAndAppend<CachedDisplayItem>(*this, DisplayItem::CachedDisplayItemList);
-            return;
-        }
-
-        m_previousPaintInterestRect = *interestRect;
-    }
-
-    ASSERT(interestRect);
-    paintContentsInternal(graphicsLayer, context, graphicsLayerPaintingPhase, *interestRect);
+    IntRect newInterestRect = recomputeInterestRect(graphicsLayer, m_owningLayer.layoutObject());
+    if (interestRectChangedEnoughToRepaint(previousInterestRect, newInterestRect, expandedIntSize(graphicsLayer->size())))
+        return newInterestRect;
+    return previousInterestRect;
 }
 
-void CompositedLayerMapping::paintContentsInternal(const GraphicsLayer* graphicsLayer, GraphicsContext& context, GraphicsLayerPaintingPhase graphicsLayerPaintingPhase, const IntRect& interestRect) const
+bool CompositedLayerMapping::needsRepaint() const
+{
+    return m_owningLayer.needsRepaint();
+}
+
+void CompositedLayerMapping::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& context, GraphicsLayerPaintingPhase graphicsLayerPaintingPhase, const IntRect& interestRect) const
 {
     // https://code.google.com/p/chromium/issues/detail?id=343772
     DisableCompositingQueryAsserts disabler;
 #if ENABLE(ASSERT)
     // FIXME: once the state machine is ready, this can be removed and we can refer to that instead.
     if (Page* page = layoutObject()->frame()->page())
         page->setIsPainting(true);
 #endif
 
     TRACE_EVENT1("devtools.timeline", "Paint", "data", InspectorPaintEvent::data(m_owningLayer.layoutObject(), LayoutRect(interestRect), graphicsLayer));
@@ skipping 178 matching lines @@
         // before removing all the extra entries.
         for (size_t i = nextSquashedLayerIndex; i < m_squashedLayers.size(); ++i) {
             if (invalidateLayerIfNoPrecedingEntry(i))
                 m_squashedLayers[i].paintLayer->setGroupedMapping(nullptr, PaintLayer::DoNotInvalidateLayerAndRemoveFromMapping);
         }
 
         m_squashedLayers.remove(nextSquashedLayerIndex, m_squashedLayers.size() - nextSquashedLayerIndex);
     }
 }
 
-String CompositedLayerMapping::debugName(const GraphicsLayer* graphicsLayer)
+String CompositedLayerMapping::debugName(const GraphicsLayer* graphicsLayer) const
 {
     String name;
     if (graphicsLayer == m_graphicsLayer.get()) {
         name = m_owningLayer.debugName();
     } else if (graphicsLayer == m_squashingContainmentLayer.get()) {
         name = "Squashing Containment Layer";
     } else if (graphicsLayer == m_squashingLayer.get()) {
         name = "Squashing Layer (first squashed layer: " + (m_squashedLayers.size() > 0 ? m_squashedLayers[0].paintLayer->debugName() : "") + ")";
     } else if (graphicsLayer == m_ancestorClippingLayer.get()) {
         name = "Ancestor Clipping Layer";
@@ skipping 26 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink