InPrePaint document state and PrePaintTreeWalk class

third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp

Index: third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
index c0af44360b8e6d06790ee0db578b4d7fa2e4000b..b215ab15b4383a7d77e484f80a95c6c899f813be 100644
--- a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
@@ -11,92 +11,29 @@
 #include "core/layout/LayoutPart.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintLayer.h"
-#include "platform/graphics/paint/ClipPaintPropertyNode.h"
-#include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "platform/transforms/TransformationMatrix.h"
 
 namespace blink {
 
-// The context for layout tree walk.
-// The walk will be done in the primary tree order (= DOM order), thus the context will also be
-// responsible for bookkeeping tree state in other order, for example, the most recent position
-// container seen.
-struct PaintPropertyTreeBuilderContext {
-    PaintPropertyTreeBuilderContext()
-        : currentTransform(nullptr)
-        , currentClip(nullptr)
-        , transformForAbsolutePosition(nullptr)
-        , containerForAbsolutePosition(nullptr)
-        , clipForAbsolutePosition(nullptr)
-        , transformForFixedPosition(nullptr)
-        , clipForFixedPosition(nullptr)
-        , currentEffect(nullptr) { }
-
-    // The combination of a transform and paint offset describes a linear space.
-    // When a layout object recur to its children, the main context is expected to refer
-    // the object's border box, then the callee will derive its own border box by translating
-    // the space with its own layout location.
-    TransformPaintPropertyNode* currentTransform;
-    LayoutPoint paintOffset;
-    // The clip node describes the accumulated raster clip for the current subtree.
-    // Note that the computed raster region in canvas space for a clip node is independent from
-    // the transform and paint offset above. Also the actual raster region may be affected
-    // by layerization and occlusion tracking.
-    ClipPaintPropertyNode* currentClip;
-
-    // Separate context for out-of-flow positioned and fixed positioned elements are needed
-    // because they don't use DOM parent as their containing block.
-    // These additional contexts normally pass through untouched, and are only copied from
-    // the main context when the current element serves as the containing block of corresponding
-    // positioned descendants.
-    // Overflow clips are also inherited by containing block tree instead of DOM tree, thus they
-    // are included in the additional context too.
-    TransformPaintPropertyNode* transformForAbsolutePosition;
-    LayoutPoint paintOffsetForAbsolutePosition;
-    LayoutObject* containerForAbsolutePosition;
-    ClipPaintPropertyNode* clipForAbsolutePosition;
-
-    TransformPaintPropertyNode* transformForFixedPosition;
-    LayoutPoint paintOffsetForFixedPosition;
-    ClipPaintPropertyNode* clipForFixedPosition;
-
-    // The effect hierarchy is applied by the stacking context tree. It is guaranteed that every
-    // DOM descendant is also a stacking context descendant. Therefore, we don't need extra
-    // bookkeeping for effect nodes and can generate the effect tree from a DOM-order traversal.
-    EffectPaintPropertyNode* currentEffect;
-};
-
-void PaintPropertyTreeBuilder::buildPropertyTrees(FrameView& rootFrame)
+void PaintPropertyTreeBuilder::buildTreeRootNodes(FrameView& rootFrame, PaintPropertyTreeBuilderRootContext& rootContext)
 {
-    PaintPropertyTreeBuilderContext rootContext;
-
-    // We don't retain permanent reference of these nodes except by child nodes.
-    // Keeps local reference until the walk finishes.
-    RefPtr<TransformPaintPropertyNode> transformRoot;
-    RefPtr<ClipPaintPropertyNode> clipRoot;
-    RefPtr<EffectPaintPropertyNode> effectRoot;
-
     // Only create extra root clip and transform nodes when RLS is enabled, because the main frame
     // unconditionally create frame translation / clip nodes otherwise.
     if (rootFrame.frame().settings() && rootFrame.frame().settings()->rootLayerScrolls()) {
-        transformRoot = TransformPaintPropertyNode::create(TransformationMatrix(), FloatPoint3D(), nullptr);
-        rootContext.currentTransform = rootContext.transformForAbsolutePosition = rootContext.transformForFixedPosition = transformRoot.get();
+        rootContext.transformRoot = TransformPaintPropertyNode::create(TransformationMatrix(), FloatPoint3D(), nullptr);
+        rootContext.currentTransform = rootContext.transformForAbsolutePosition = rootContext.transformForFixedPosition = rootContext.transformRoot.get();
 
-        clipRoot = ClipPaintPropertyNode::create(transformRoot, FloatRoundedRect(LayoutRect::infiniteIntRect()), nullptr);
-        rootContext.currentClip = rootContext.clipForAbsolutePosition = rootContext.clipForFixedPosition = clipRoot.get();
+        rootContext.clipRoot = ClipPaintPropertyNode::create(rootContext.transformRoot, FloatRoundedRect(LayoutRect::infiniteIntRect()), nullptr);
+        rootContext.currentClip = rootContext.clipForAbsolutePosition = rootContext.clipForFixedPosition = rootContext.clipRoot.get();
     }
 
     // The root frame never creates effect node so we unconditionally create a root node here.
-    effectRoot = EffectPaintPropertyNode::create(1.0, nullptr);
-    rootContext.currentEffect = effectRoot.get();
-
-    walk(rootFrame, rootContext);
+    rootContext.effectRoot = EffectPaintPropertyNode::create(1.0, nullptr);
+    rootContext.currentEffect = rootContext.effectRoot.get();
 }
 
-void PaintPropertyTreeBuilder::walk(FrameView& frameView, const PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::buildTreeNodes(FrameView& frameView, PaintPropertyTreeBuilderContext& context)
 {
-    PaintPropertyTreeBuilderContext localContext(context);
-
     // TODO(pdr): Creating paint properties for FrameView here will not be
     // needed once settings()->rootLayerScrolls() is enabled.
     // TODO(pdr): Make this conditional on the rootLayerScrolls setting.
@@ -104,31 +41,28 @@ void PaintPropertyTreeBuilder::walk(FrameView& frameView, const PaintPropertyTre
     TransformationMatrix frameTranslate;
     frameTranslate.translate(frameView.x() + context.paintOffset.x(), frameView.y() + context.paintOffset.y());
     RefPtr<TransformPaintPropertyNode> newTransformNodeForPreTranslation = TransformPaintPropertyNode::create(frameTranslate, FloatPoint3D(), context.currentTransform);
-    localContext.transformForFixedPosition = newTransformNodeForPreTranslation.get();
-    localContext.paintOffsetForFixedPosition = LayoutPoint();
+    context.transformForFixedPosition = newTransformNodeForPreTranslation.get();
+    context.paintOffsetForFixedPosition = LayoutPoint();
 
     FloatRoundedRect contentClip(IntRect(IntPoint(), frameView.visibleContentSize()));
-    RefPtr<ClipPaintPropertyNode> newClipNodeForContentClip = ClipPaintPropertyNode::create(newTransformNodeForPreTranslation.get(), contentClip, localContext.currentClip);
-    localContext.currentClip = localContext.clipForAbsolutePosition = localContext.clipForFixedPosition = newClipNodeForContentClip.get();
+    RefPtr<ClipPaintPropertyNode> newClipNodeForContentClip = ClipPaintPropertyNode::create(newTransformNodeForPreTranslation.get(), contentClip, context.currentClip);
+    context.currentClip = context.clipForAbsolutePosition = context.clipForFixedPosition = newClipNodeForContentClip.get();
 
     DoubleSize scrollOffset = frameView.scrollOffsetDouble();
     TransformationMatrix frameScroll;
     frameScroll.translate(-scrollOffset.width(), -scrollOffset.height());
     RefPtr<TransformPaintPropertyNode> newTransformNodeForScrollTranslation = TransformPaintPropertyNode::create(frameScroll, FloatPoint3D(), newTransformNodeForPreTranslation);
-    localContext.currentTransform = localContext.transformForAbsolutePosition = newTransformNodeForScrollTranslation.get();
-    localContext.paintOffset = LayoutPoint();
-    localContext.paintOffsetForAbsolutePosition = LayoutPoint();
-    localContext.containerForAbsolutePosition = nullptr;
+    context.currentTransform = context.transformForAbsolutePosition = newTransformNodeForScrollTranslation.get();
+    context.paintOffset = LayoutPoint();
+    context.paintOffsetForAbsolutePosition = LayoutPoint();
+    context.containerForAbsolutePosition = nullptr;
 
     frameView.setPreTranslation(newTransformNodeForPreTranslation.release());
     frameView.setScrollTranslation(newTransformNodeForScrollTranslation.release());
     frameView.setContentClip(newClipNodeForContentClip.release());
-
-    if (LayoutView* layoutView = frameView.layoutView())
-        walk(*layoutView, localContext);
 }
 
-void PaintPropertyTreeBuilder::updatePaintOffsetTranslation(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updatePaintOffsetTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     bool shouldCreatePaintOffsetTranslationNode = false;
     if (object.isSVGRoot()) {
@@ -148,7 +82,7 @@ void PaintPropertyTreeBuilder::updatePaintOffsetTranslation(LayoutObject& object
         FloatPoint3D(), context.currentTransform);
     context.currentTransform = paintOffsetTranslation.get();
     context.paintOffset = LayoutPoint();
-    object.ensureObjectPaintProperties().setPaintOffsetTranslation(paintOffsetTranslation.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setPaintOffsetTranslation(paintOffsetTranslation.release());
 }
 
 static FloatPoint3D transformOrigin(const LayoutBox& box)
@@ -161,7 +95,7 @@ static FloatPoint3D transformOrigin(const LayoutBox& box)
         style.transformOriginZ());
 }
 
-void PaintPropertyTreeBuilder::updateTransform(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateTransform(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     const ComputedStyle& style = object.styleRef();
     if (!object.isBox() || !style.hasTransform())
@@ -174,19 +108,19 @@ void PaintPropertyTreeBuilder::updateTransform(LayoutObject& object, PaintProper
     RefPtr<TransformPaintPropertyNode> transformNode = TransformPaintPropertyNode::create(
         matrix, transformOrigin(toLayoutBox(object)), context.currentTransform);
     context.currentTransform = transformNode.get();
-    object.ensureObjectPaintProperties().setTransform(transformNode.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setTransform(transformNode.release());
 }
 
-void PaintPropertyTreeBuilder::updateEffect(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateEffect(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.styleRef().hasOpacity())
         return;
     RefPtr<EffectPaintPropertyNode> effectNode = EffectPaintPropertyNode::create(object.styleRef().opacity(), context.currentEffect);
     context.currentEffect = effectNode.get();
-    object.ensureObjectPaintProperties().setEffect(effectNode.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setEffect(effectNode.release());
 }
 
-void PaintPropertyTreeBuilder::updateCssClip(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateCssClip(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.hasClip())
         return;
@@ -202,10 +136,10 @@ void PaintPropertyTreeBuilder::updateCssClip(LayoutObject& object, PaintProperty
         FloatRoundedRect(FloatRect(clipRect)),
         context.currentClip);
     context.currentClip = clipNode.get();
-    object.ensureObjectPaintProperties().setCssClip(clipNode.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setCssClip(clipNode.release());
 }
 
-void PaintPropertyTreeBuilder::updateLocalBorderBoxContext(LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateLocalBorderBoxContext(const LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
 {
     // Note: Currently only layer painter makes use of the pre-computed context.
     // This condition may be loosened with no adverse effects beside memory use.
@@ -218,11 +152,11 @@ void PaintPropertyTreeBuilder::updateLocalBorderBoxContext(LayoutObject& object,
     borderBoxContext->transform = context.currentTransform;
     borderBoxContext->clip = context.currentClip;
     borderBoxContext->effect = context.currentEffect;
-    object.ensureObjectPaintProperties().setLocalBorderBoxProperties(std::move(borderBoxContext));
+    object.getMutableForPainting().ensureObjectPaintProperties().setLocalBorderBoxProperties(std::move(borderBoxContext));
 }
 
 // TODO(trchen): Remove this once we bake the paint offset into frameRect.
-void PaintPropertyTreeBuilder::updateScrollbarPaintOffset(LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateScrollbarPaintOffset(const LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
 {
     IntPoint roundedPaintOffset = roundedIntPoint(context.paintOffset);
     if (roundedPaintOffset == IntPoint())
@@ -237,11 +171,11 @@ void PaintPropertyTreeBuilder::updateScrollbarPaintOffset(LayoutObject& object,
         return;
 
     auto paintOffset = TransformationMatrix().translate(roundedPaintOffset.x(), roundedPaintOffset.y());
-    object.ensureObjectPaintProperties().setScrollbarPaintOffset(
+    object.getMutableForPainting().ensureObjectPaintProperties().setScrollbarPaintOffset(
         TransformPaintPropertyNode::create(paintOffset, FloatPoint3D(), context.currentTransform));
 }
 
-void PaintPropertyTreeBuilder::updateOverflowClip(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateOverflowClip(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isBox())
         return;
@@ -272,7 +206,7 @@ void PaintPropertyTreeBuilder::updateOverflowClip(LayoutObject& object, PaintPro
         FloatRoundedRect(FloatRect(clipRect)),
         borderRadiusClip ? borderRadiusClip.release() : context.currentClip);
     context.currentClip = overflowClip.get();
-    object.ensureObjectPaintProperties().setOverflowClip(overflowClip.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setOverflowClip(overflowClip.release());
 }
 
 static FloatPoint perspectiveOrigin(const LayoutBox& box)
@@ -284,7 +218,7 @@ static FloatPoint perspectiveOrigin(const LayoutBox& box)
         floatValueForLength(style.perspectiveOriginY(), borderBoxSize.height()));
 }
 
-void PaintPropertyTreeBuilder::updatePerspective(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updatePerspective(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     const ComputedStyle& style = object.styleRef();
     if (!object.isBox() || !style.hasPerspective())
@@ -295,10 +229,10 @@ void PaintPropertyTreeBuilder::updatePerspective(LayoutObject& object, PaintProp
         perspectiveOrigin(toLayoutBox(object)) + toLayoutSize(context.paintOffset),
         context.currentTransform);
     context.currentTransform = perspective.get();
-    object.ensureObjectPaintProperties().setPerspective(perspective.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setPerspective(perspective.release());
 }
 
-void PaintPropertyTreeBuilder::updateSvgLocalTransform(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateSvgLocalTransform(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isSVG())
         return;
@@ -311,10 +245,10 @@ void PaintPropertyTreeBuilder::updateSvgLocalTransform(LayoutObject& object, Pai
     RefPtr<TransformPaintPropertyNode> svgLocalTransform = TransformPaintPropertyNode::create(
         transform, FloatPoint3D(0, 0, 0), context.currentTransform);
     context.currentTransform = svgLocalTransform.get();
-    object.ensureObjectPaintProperties().setSvgLocalTransform(svgLocalTransform.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setSvgLocalTransform(svgLocalTransform.release());
 }
 
-void PaintPropertyTreeBuilder::updateScrollTranslation(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateScrollTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isBoxModelObject() || !object.hasOverflowClip())
         return;
@@ -330,10 +264,10 @@ void PaintPropertyTreeBuilder::updateScrollTranslation(LayoutObject& object, Pai
         FloatPoint3D(),
         context.currentTransform);
     context.currentTransform = scrollTranslation.get();
-    object.ensureObjectPaintProperties().setScrollTranslation(scrollTranslation.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setScrollTranslation(scrollTranslation.release());
 }
 
-void PaintPropertyTreeBuilder::updateOutOfFlowContext(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateOutOfFlowContext(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (object.canContainAbsolutePositionObjects()) {
         context.transformForAbsolutePosition = context.currentTransform;
@@ -368,7 +302,7 @@ void PaintPropertyTreeBuilder::updateOutOfFlowContext(LayoutObject& object, Pain
             cssClip->clipRect(),
             context.clipForFixedPosition);
         context.clipForFixedPosition = clipFixedPosition.get();
-        object.ensureObjectPaintProperties().setCssClipFixedPosition(clipFixedPosition.release());
+        object.getMutableForPainting().ensureObjectPaintProperties().setCssClipFixedPosition(clipFixedPosition.release());
     }
 }
 
@@ -390,7 +324,7 @@ static void deriveBorderBoxFromContainerContext(const LayoutObject& object, Pain
         context.paintOffset = context.paintOffsetForAbsolutePosition;
 
         // Absolutely positioned content in an inline should be positioned relative to the inline.
-        LayoutObject* container = context.containerForAbsolutePosition;
+        const LayoutObject* container = context.containerForAbsolutePosition;
         if (container && container->isInFlowPositioned() && container->isLayoutInline()) {
             DCHECK(object.isBox());
             context.paintOffset += toLayoutInline(container)->offsetForInFlowPositionedInline(toLayoutBox(object));
@@ -423,38 +357,25 @@ static void deriveBorderBoxFromContainerContext(const LayoutObject& object, Pain
     }
 }
 
-void PaintPropertyTreeBuilder::walk(LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::buildTreeNodes(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
-    PaintPropertyTreeBuilderContext localContext(context);
-    object.clearObjectPaintProperties();
-
-    deriveBorderBoxFromContainerContext(object, localContext);
-
-    updatePaintOffsetTranslation(object, localContext);
-    updateTransform(object, localContext);
-    updateEffect(object, localContext);
-    updateCssClip(object, localContext);
-    updateLocalBorderBoxContext(object, localContext);
-    updateScrollbarPaintOffset(object, localContext);
-    updateOverflowClip(object, localContext);
+    object.getMutableForPainting().clearObjectPaintProperties();
+
+    deriveBorderBoxFromContainerContext(object, context);
+
+    updatePaintOffsetTranslation(object, context);
+    updateTransform(object, context);
+    updateEffect(object, context);
+    updateCssClip(object, context);
+    updateLocalBorderBoxContext(object, context);
+    updateScrollbarPaintOffset(object, context);
+    updateOverflowClip(object, context);
     // TODO(trchen): Insert flattening transform here, as specified by
     // http://www.w3.org/TR/css3-transforms/#transform-style-property
-    updatePerspective(object, localContext);
-    updateSvgLocalTransform(object, localContext);
-    updateScrollTranslation(object, localContext);
-    updateOutOfFlowContext(object, localContext);
-
-    for (LayoutObject* child = object.slowFirstChild(); child; child = child->nextSibling()) {
-        if (child->isBoxModelObject() || child->isSVG())
-            walk(*child, localContext);
-    }
-
-    if (object.isLayoutPart()) {
-        Widget* widget = toLayoutPart(object).widget();
-        if (widget && widget->isFrameView())
-            walk(*toFrameView(widget), localContext);
-        // TODO(pdr): Investigate RemoteFrameView (crbug.com/579281).
-    }
+    updatePerspective(object, context);
+    updateSvgLocalTransform(object, context);
+    updateScrollTranslation(object, context);
+    updateOutOfFlowContext(object, context);
 }
 
 } // namespace blink