Enable fast/images with slimming paint

Source/core/paint/ClipRecorder.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/ClipRecorder.h"
 
-#include "core/rendering/ClipRect.h"
-#include "core/rendering/RenderLayer.h"
+#include "core/paint/ViewDisplayList.h"
+#include "core/rendering/PaintInfo.h"
+#include "core/rendering/RenderLayerModelObject.h"
 #include "core/rendering/RenderView.h"
 #include "platform/RuntimeEnabledFeatures.h"
-#include "platform/geometry/IntRect.h"
-#include "platform/graphics/GraphicsContext.h"
 
 namespace blink {
 
-void ClipDisplayItem::replay(GraphicsContext* context)
+ClipRecorder::ClipRecorder(RenderLayerModelObject& canvas, const PaintInfo& paintInfo, const LayoutRect& clipRect)
+    : m_clipRect(clipRect)
+    , m_paintInfo(paintInfo)
+    , m_canvas(canvas)
 {
-    context->save();
-    context->clip(m_clipRect);
-    for (RoundedRect roundedRect : m_roundedRectClips)
-        context->clipRoundedRect(roundedRect);
-}
+    DisplayItem::Type type = paintPhaseToClipType(paintInfo.phase);
+    OwnPtr<ClipDisplayItem> clipDisplayItem = adoptPtr(new ClipDisplayItem(&m_canvas, type, pixelSnappedIntRect(clipRect)));
 
-void EndClipDisplayItem::replay(GraphicsContext* context)
-{
-    context->restore();
-}
-
-ClipRecorder::ClipRecorder(const RenderLayerModelObject* renderer, GraphicsContext* graphicsContext, DisplayItem::Type clipType, const ClipRect& clipRect,
-    const LayerPaintingInfo* localPaintingInfo, const LayoutPoint& fragmentOffset, PaintLayerFlags paintFlags, BorderRadiusClippingRule rule)
-    : m_graphicsContext(graphicsContext)
-    , m_renderer(renderer)
-{
-    IntRect snappedClipRect = pixelSnappedIntRect(clipRect.rect());
-    OwnPtr<ClipDisplayItem> clipDisplayItem = adoptPtr(new ClipDisplayItem(renderer, clipType, snappedClipRect));
-    if (localPaintingInfo && clipRect.hasRadius())
-        collectRoundedRectClips(*renderer->layer(), *localPaintingInfo, graphicsContext, fragmentOffset, paintFlags, rule, clipDisplayItem->roundedRectClips());
-    if (!RuntimeEnabledFeatures::slimmingPaintEnabled()) {
-        clipDisplayItem->replay(graphicsContext);
-    } else {
-        m_renderer->view()->viewDisplayList().add(clipDisplayItem.release());
-    }
-}
-
-static bool inContainingBlockChain(RenderLayer* startLayer, RenderLayer* endLayer)
-{
-    if (startLayer == endLayer)
-        return true;
-
-    RenderView* view = startLayer->renderer()->view();
-    for (RenderBlock* currentBlock = startLayer->renderer()->containingBlock(); currentBlock && currentBlock != view; currentBlock = currentBlock->containingBlock()) {
-        if (currentBlock->layer() == endLayer)
-            return true;
-    }
-
-    return false;
-}
-
-void ClipRecorder::collectRoundedRectClips(RenderLayer& renderLayer, const LayerPaintingInfo& localPaintingInfo, GraphicsContext* context, const LayoutPoint& fragmentOffset, PaintLayerFlags paintFlags,
-    BorderRadiusClippingRule rule, Vector<RoundedRect>& roundedRectClips)
-{
-    // If the clip rect has been tainted by a border radius, then we have to walk up our layer chain applying the clips from
-    // any layers with overflow. The condition for being able to apply these clips is that the overflow object be in our
-    // containing block chain so we check that also.
-    for (RenderLayer* layer = rule == IncludeSelfForBorderRadius ? &renderLayer : renderLayer.parent(); layer; layer = layer->parent()) {
-        // Composited scrolling layers handle border-radius clip in the compositor via a mask layer. We do not
-        // want to apply a border-radius clip to the layer contents itself, because that would require re-rastering
-        // every frame to update the clip. We only want to make sure that the mask layer is properly clipped so
-        // that it can in turn clip the scrolled contents in the compositor.
-        if (layer->needsCompositedScrolling() && !(paintFlags & PaintLayerPaintingChildClippingMaskPhase))
-            break;
-
-        if (layer->renderer()->hasOverflowClip() && layer->renderer()->style()->hasBorderRadius() && inContainingBlockChain(&renderLayer, layer)) {
-            LayoutPoint delta(fragmentOffset);
-            layer->convertToLayerCoords(localPaintingInfo.rootLayer, delta);
-            roundedRectClips.append(layer->renderer()->style()->getRoundedInnerBorderFor(LayoutRect(delta, LayoutSize(layer->size()))));
-        }
-
-        if (layer == localPaintingInfo.rootLayer)
-            break;
-    }
+    if (RuntimeEnabledFeatures::slimmingPaintEnabled())
+        m_canvas.view()->viewDisplayList().add(clipDisplayItem.release());
+    else
+        clipDisplayItem->replay(paintInfo.context);
 }
 
 ClipRecorder::~ClipRecorder()
 {
+    OwnPtr<EndClipDisplayItem> endClipDisplayItem = adoptPtr(new EndClipDisplayItem(&m_canvas));
+
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
-        OwnPtr<EndClipDisplayItem> endClip = adoptPtr(new EndClipDisplayItem(m_renderer));
-        m_renderer->view()->viewDisplayList().add(endClip.release());
+        m_canvas.view()->viewDisplayList().add(endClipDisplayItem.release());
     } else {
-        m_graphicsContext->restore();
+        endClipDisplayItem->replay(m_paintInfo.context);
     }
 }
 
-#ifndef NDEBUG
-WTF::String ClipDisplayItem::asDebugString() const
+DisplayItem::Type ClipRecorder::paintPhaseToClipType(PaintPhase paintPhase)
 {
-    return String::format("{%s, type: \"%s\", clipRect: [%d,%d,%d,%d]}",
-        rendererDebugString(renderer()).utf8().data(), typeAsDebugString(type()).utf8().data(),
-        m_clipRect.x(), m_clipRect.y(), m_clipRect.width(), m_clipRect.height());
+    switch (paintPhase) {
+    case PaintPhaseChildBlockBackgrounds:
+        return DisplayItem::ClipBoxChildBlockBackgrounds;
+        break;
+    case PaintPhaseFloat:
+        return DisplayItem::ClipBoxFloat;
+        break;
+    case PaintPhaseForeground:
+        return DisplayItem::ClipBoxChildBlockBackgrounds;
+        break;
+    case PaintPhaseChildOutlines:
+        return DisplayItem::ClipBoxChildOutlines;
+        break;
+    case PaintPhaseSelection:
+        return DisplayItem::ClipBoxSelection;
+        break;
+    case PaintPhaseCollapsedTableBorders:
+        return DisplayItem::ClipBoxCollapsedTableBorders;
+        break;
+    case PaintPhaseTextClip:
+        return DisplayItem::ClipBoxTextClip;
+        break;
+    case PaintPhaseClippingMask:
+        return DisplayItem::ClipBoxClippingMask;
+        break;
+    case PaintPhaseChildBlockBackground:
+    case PaintPhaseOutline:
+    case PaintPhaseBlockBackground:
+    case PaintPhaseSelfOutline:
+    case PaintPhaseMask:
+        ASSERT_NOT_REACHED();
+    }
+    // This should never happen.
+    return DisplayItem::ClipBoxForeground;
 }
-#endif
 
 } // namespace blink