Add support for SVG Clip paths in HTML

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index ea83bc9e465458e5b59d3e73b430a8b72a3eb3e3..38773d5b4e04a31ed25b6ee8582c508329683077 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -1841,26 +1841,21 @@ void RenderLayer::paintLayerContents(GraphicsContext* context, const LayerPainti
             }
 
             context->clipPath(clipPath->path(rootRelativeBounds), clipPath->windRule());
-        } else if (style->clipPath()->type() == ClipPathOperation::REFERENCE) {
-            ReferenceClipPathOperation* referenceClipPathOperation = toReferenceClipPathOperation(style->clipPath());
-            Document& document = renderer()->document();
+        } else if (m_clipPathInfo && m_clipPathInfo->getClipPathElement() && m_clipPathInfo->getClipPathElement()->renderer()) {
             // FIXME: It doesn't work with forward or external SVG references (https://bugs.webkit.org/show_bug.cgi?id=90405)
-            Element* element = document.getElementById(referenceClipPathOperation->fragment());
-            if (isSVGClipPathElement(element) && element->renderer()) {
-                // FIXME: Saving at this point is not required in the 'mask'-
-                // case, or if the clip ends up empty.
-                clipStateSaver.save();
-                if (!rootRelativeBoundsComputed) {
-                    rootRelativeBounds = physicalBoundingBoxIncludingReflectionAndStackingChildren(paintingInfo.rootLayer, offsetFromRoot);
-                    rootRelativeBoundsComputed = true;
-                }
+            // FIXME: Saving at this point is not required in the 'mask'-
+            // case, or if the clip ends up empty.
+            clipStateSaver.save();
+            if (!rootRelativeBoundsComputed) {
+                rootRelativeBounds = physicalBoundingBoxIncludingReflectionAndStackingChildren(paintingInfo.rootLayer, offsetFromRoot);
+                rootRelativeBoundsComputed = true;
+            }
 
-                resourceClipper = toRenderSVGResourceClipper(toRenderSVGResourceContainer(element->renderer()));
-                if (!resourceClipper->applyClippingToContext(renderer(), rootRelativeBounds,
-                    paintingInfo.paintDirtyRect, context, clipperContext)) {
-                    // No need to post-apply the clipper if this failed.
-                    resourceClipper = 0;
-                }
+            resourceClipper = toRenderSVGResourceClipper(toRenderSVGResourceContainer(m_clipPathInfo->getClipPathElement()->renderer()));
+            if (!resourceClipper->applyClippingToContext(renderer(), rootRelativeBounds,
+                paintingInfo.paintDirtyRect, context, clipperContext)) {
+                // No need to post-apply the clipper if this failed.
+                resourceClipper = 0;
             }
         }
     }
@@ -3549,6 +3544,20 @@ void RenderLayer::updateFilters(const RenderStyle* oldStyle, const RenderStyle*
     updateOrRemoveFilterEffectRenderer();
 }
 
+void RenderLayer::updateClipPathInfo(const RenderStyle* oldStyle, const RenderStyle* newStyle)
+{
+    if (!newStyle->clipPath() && (!oldStyle || !oldStyle->clipPath()))
+        return;
+
+    if (renderer()->hasClipPath() && renderer()->style()->clipPath()->type() == ClipPathOperation::REFERENCE) {
+        if (!m_clipPathInfo)
+            m_clipPathInfo = adoptPtr(new RenderLayerClipPathInfo(this));
+        m_clipPathInfo->updateReferenceClipPathClients(renderer()->style()->clipPath());
+    } else if (m_clipPathInfo) {
+        m_clipPathInfo = nullptr;
+    }
+}
+
 bool RenderLayer::attemptDirectCompositingUpdate(StyleDifference diff, const RenderStyle* oldStyle)
 {
     CompositingReasons oldPotentialCompositingReasonsFromStyle = m_potentialCompositingReasonsFromStyle;
@@ -3571,12 +3580,12 @@ bool RenderLayer::attemptDirectCompositingUpdate(StyleDifference diff, const Ren
     // the reflection layers.
     if (renderer()->hasReflection())
         return false;
-    // If we're unwinding a scheduleSVGFilterLayerUpdateHack(), then we can't
+    // If we're unwinding a scheduleSVGEffectsLayerUpdateHack(), then we can't
     // perform a direct compositing update because the filters code is going
     // to produce different output this time around. We can remove this code
     // once we fix the chicken/egg bugs in the filters code and delete the
-    // scheduleSVGFilterLayerUpdateHack().
-    if (renderer()->node() && renderer()->node()->svgFilterNeedsLayerUpdate())
+    // scheduleSVGEffectsLayerUpdateHack().
+    if (renderer()->node() && renderer()->node()->svgEffectsNeedLayerUpdate())
         return false;
     if (!m_compositedLayerMapping)
         return false;
@@ -3627,6 +3636,8 @@ void RenderLayer::styleChanged(StyleDifference diff, const RenderStyle* oldStyle
         updateReflectionInfo(oldStyle);
     }
 
+    updateClipPathInfo(oldStyle, renderer()->style());
+
     if (RuntimeEnabledFeatures::cssCompositingEnabled())
         m_blendInfo.updateBlendMode();
 
@@ -3714,15 +3725,15 @@ void RenderLayer::updateOrRemoveFilterEffectRenderer()
         filterInfo->setRenderer(nullptr);
 }
 
-void RenderLayer::filterNeedsPaintInvalidation()
+void RenderLayer::svgEffectsNeedPaintInvalidation()

[esprehn, 2014/08/06 17:25:10]

We should not be adding more callers of this or
scheduleSVGEffectsLayerUpdateHack.

 {
     {
         DeprecatedScheduleStyleRecalcDuringLayout marker(renderer()->document().lifecycle());
-        // It's possible for scheduleSVGFilterLayerUpdateHack to schedule a style recalc, which
+        // It's possible for scheduleSVGEffectsLayerUpdateHack to schedule a style recalc, which
         // is a problem because this function can be called while performing layout.
         // Presumably this represents an illegal data flow of layout or compositing
         // information into the style system.
-        toElement(renderer()->node())->scheduleSVGFilterLayerUpdateHack();
+        toElement(renderer()->node())->scheduleSVGEffectsLayerUpdateHack();
     }
 
     if (renderer()->view()) {