Late-loading stylesheets can cause composited layers to be blank

https://bugs.webkit.org/show_bug.cgi?id=103773

Reviewed by Tim Horton.

Early painting can be short-circuited in RenderBlock::paintContents() if we know a stylesheet
is pending, which is done to avoid a flash of unstyled content (FOUC). When the stylesheet
finally loaded, Document::styleResolverChanged() would try to repaint everything by calling
repaint() on the RenderView(). In a composited world, however, this repaint() doesn't repaint
composited layers.

This was particularly prevalent on this specific URL because it failed to load
a CSS file from typekit.com, so Document::styleResolverChanged()
just did the repaint and returned (rather than doing a recalc style as would
happen for correctly loaded stylesheets).

Fix by making a way to repaint all compositing layers, and calling it
from Document::styleResolverChanged().

No tests because this is timing-dependant.

* dom/Document.cpp:
(WebCore::Document::styleResolverChanged): Call repaintViewAndCompositedLayers().
* rendering/RenderBlock.cpp:
(WebCore::RenderBlock::paintContents): Fix the comment.
* rendering/RenderLayerCompositor.cpp: Convert repaintCompositedLayersAbsoluteRect()
and associated recursiveRepaintLayerRect() to allow the rect to be null, which indicates
that we should just repaint the entire layer, and improve their names.
(WebCore::RenderLayerCompositor::repaintCompositedLayers):
(WebCore::RenderLayerCompositor::recursiveRepaintLayer):
* rendering/RenderLayerCompositor.h:
* rendering/RenderView.cpp:
(WebCore::RenderView::repaintRectangleInViewAndCompositedLayers): repaintCompositedLayersAbsoluteRect()
was renamed to repaintCompositedLayers().
(WebCore::RenderView::repaintViewAndCompositedLayers):
* rendering/RenderView.h:
(RenderView): repaintViewRectangle() and repaintRectangleInViewAndCompositedLayers() should not
be virtual. Add repaintViewAndCompositedLayers().

Change-Id: I86401d25d06128db33a5e5db099144d6b05850ef
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@136277 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>

6 files changed, 49 insertions, 23 deletions

diff --git a/Source/WebCore/dom/Document.cpp b/Source/WebCore/dom/Document.cpp
index c1c2b7b5d..ec7ca673e 100644
--- a/Source/WebCore/dom/Document.cpp
+++ b/Source/WebCore/dom/Document.cpp
@@ -3179,7 +3179,7 @@ void Document::styleResolverChanged(StyleResolverUpdateFlag updateFlag)
     if (didLayoutWithPendingStylesheets() && !m_styleSheetCollection->hasPendingSheets()) {
         m_pendingSheetLayout = IgnoreLayoutWithPendingSheets;
         if (renderer())
-            renderer()->repaint();
+            renderView()->repaintViewAndCompositedLayers();
     }
 
     if (!stylesheetChangeRequiresStyleRecalc)
diff --git a/Source/WebCore/rendering/RenderBlock.cpp b/Source/WebCore/rendering/RenderBlock.cpp
index 4265ecdf3..058e90431 100644
--- a/Source/WebCore/rendering/RenderBlock.cpp
+++ b/Source/WebCore/rendering/RenderBlock.cpp
@@ -2925,8 +2925,8 @@ void RenderBlock::paintColumnContents(PaintInfo& paintInfo, const LayoutPoint& p
 void RenderBlock::paintContents(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     // Avoid painting descendants of the root element when stylesheets haven't loaded.  This eliminates FOUC.
-    // It's ok not to draw, because later on, when all the stylesheets do load, updateStyleSelector on the Document
-    // will do a full repaint().
+    // It's ok not to draw, because later on, when all the stylesheets do load, styleResolverChanged() on the Document
+    // will do a full repaint.
     if (document()->didLayoutWithPendingStylesheets() && !isRenderView())
         return;
 
diff --git a/Source/WebCore/rendering/RenderLayerCompositor.cpp b/Source/WebCore/rendering/RenderLayerCompositor.cpp
index 870bf1ddf..3ddfe4538 100644
--- a/Source/WebCore/rendering/RenderLayerCompositor.cpp
+++ b/Source/WebCore/rendering/RenderLayerCompositor.cpp
@@ -1340,16 +1340,20 @@ void RenderLayerCompositor::updateCompositingDescendantGeometry(RenderLayer* com
 }
 
 
-void RenderLayerCompositor::repaintCompositedLayersAbsoluteRect(const IntRect& absRect)
+void RenderLayerCompositor::repaintCompositedLayers(const IntRect* absRect)
 {
-    recursiveRepaintLayerRect(rootRenderLayer(), absRect);
+    recursiveRepaintLayer(rootRenderLayer(), absRect);
 }
 
-void RenderLayerCompositor::recursiveRepaintLayerRect(RenderLayer* layer, const IntRect& rect)
+void RenderLayerCompositor::recursiveRepaintLayer(RenderLayer* layer, const IntRect* rect)
 {
     // FIXME: This method does not work correctly with transforms.
-    if (layer->isComposited() && !layer->backing()->paintsIntoCompositedAncestor())
-        layer->setBackingNeedsRepaintInRect(rect);
+    if (layer->isComposited() && !layer->backing()->paintsIntoCompositedAncestor()) {
+        if (rect)
+            layer->setBackingNeedsRepaintInRect(*rect);
+        else
+            layer->setBackingNeedsRepaint();
+    }
 
 #if !ASSERT_DISABLED
     LayerListMutationDetector mutationChecker(layer);
@@ -1360,9 +1364,12 @@ void RenderLayerCompositor::recursiveRepaintLayerRect(RenderLayer* layer, const
             size_t listSize = negZOrderList->size();
             for (size_t i = 0; i < listSize; ++i) {
                 RenderLayer* curLayer = negZOrderList->at(i);
-                IntRect childRect(rect);
-                curLayer->convertToPixelSnappedLayerCoords(layer, childRect);
-                recursiveRepaintLayerRect(curLayer, childRect);
+                if (rect) {
+                    IntRect childRect(*rect);
+                    curLayer->convertToPixelSnappedLayerCoords(layer, childRect);
+                    recursiveRepaintLayer(curLayer, &childRect);
+                } else
+                    recursiveRepaintLayer(curLayer);
             }
         }
 
@@ -1370,9 +1377,12 @@ void RenderLayerCompositor::recursiveRepaintLayerRect(RenderLayer* layer, const
             size_t listSize = posZOrderList->size();
             for (size_t i = 0; i < listSize; ++i) {
                 RenderLayer* curLayer = posZOrderList->at(i);
-                IntRect childRect(rect);
-                curLayer->convertToPixelSnappedLayerCoords(layer, childRect);
-                recursiveRepaintLayerRect(curLayer, childRect);
+                if (rect) {
+                    IntRect childRect(*rect);
+                    curLayer->convertToPixelSnappedLayerCoords(layer, childRect);
+                    recursiveRepaintLayer(curLayer, &childRect);
+                } else
+                    recursiveRepaintLayer(curLayer);
             }
         }
     }
@@ -1380,9 +1390,12 @@ void RenderLayerCompositor::recursiveRepaintLayerRect(RenderLayer* layer, const
         size_t listSize = normalFlowList->size();
         for (size_t i = 0; i < listSize; ++i) {
             RenderLayer* curLayer = normalFlowList->at(i);
-            IntRect childRect(rect);
-            curLayer->convertToPixelSnappedLayerCoords(layer, childRect);
-            recursiveRepaintLayerRect(curLayer, childRect);
+            if (rect) {
+                IntRect childRect(*rect);
+                curLayer->convertToPixelSnappedLayerCoords(layer, childRect);
+                recursiveRepaintLayer(curLayer, &childRect);
+            } else
+                recursiveRepaintLayer(curLayer);
         }
     }
 }
diff --git a/Source/WebCore/rendering/RenderLayerCompositor.h b/Source/WebCore/rendering/RenderLayerCompositor.h
index 4d828f1a5..5193411a2 100644
--- a/Source/WebCore/rendering/RenderLayerCompositor.h
+++ b/Source/WebCore/rendering/RenderLayerCompositor.h
@@ -144,8 +144,8 @@ public:
     // Get the nearest ancestor layer that has overflow or clip, but is not a stacking context
     RenderLayer* enclosingNonStackingClippingLayer(const RenderLayer* layer) const;
 
-    // Repaint parts of all composited layers that intersect the given absolute rectangle.
-    void repaintCompositedLayersAbsoluteRect(const IntRect&);
+    // Repaint parts of all composited layers that intersect the given absolute rectangle (or the entire layer if the pointer is null).
+    void repaintCompositedLayers(const IntRect* = 0);
 
     // Returns true if the given layer needs it own backing store.
     bool requiresOwnBackingStore(const RenderLayer*, const RenderLayer* compositingAncestorLayer) const;
@@ -257,7 +257,7 @@ private:
     void clearBackingForLayerIncludingDescendants(RenderLayer*);
 
     // Repaint the given rect (which is layer's coords), and regions of child layers that intersect that rect.
-    void recursiveRepaintLayerRect(RenderLayer*, const IntRect&);
+    void recursiveRepaintLayer(RenderLayer*, const IntRect* = 0);
 
     void addToOverlapMap(OverlapMap&, RenderLayer*, IntRect& layerBounds, bool& boundsComputed);
     void addToOverlapMapRecursive(OverlapMap&, RenderLayer*, RenderLayer* ancestorLayer = 0);
diff --git a/Source/WebCore/rendering/RenderView.cpp b/Source/WebCore/rendering/RenderView.cpp
index 1457b6be2..bdb9c8069 100644
--- a/Source/WebCore/rendering/RenderView.cpp
+++ b/Source/WebCore/rendering/RenderView.cpp
@@ -435,8 +435,20 @@ void RenderView::repaintRectangleInViewAndCompositedLayers(const LayoutRect& ur,
     repaintViewRectangle(ur, immediate);
     
 #if USE(ACCELERATED_COMPOSITING)
+    if (compositor()->inCompositingMode()) {
+        IntRect repaintRect = pixelSnappedIntRect(ur);
+        compositor()->repaintCompositedLayers(&repaintRect);
+    }
+#endif
+}
+
+void RenderView::repaintViewAndCompositedLayers()
+{
+    repaint();
+    
+#if USE(ACCELERATED_COMPOSITING)
     if (compositor()->inCompositingMode())
-        compositor()->repaintCompositedLayersAbsoluteRect(pixelSnappedIntRect(ur));
+        compositor()->repaintCompositedLayers();
 #endif
 }
 
diff --git a/Source/WebCore/rendering/RenderView.h b/Source/WebCore/rendering/RenderView.h
index d63f8df86..99ab1c1a3 100644
--- a/Source/WebCore/rendering/RenderView.h
+++ b/Source/WebCore/rendering/RenderView.h
@@ -78,10 +78,11 @@ public:
     FrameView* frameView() const { return m_frameView; }
 
     virtual void computeRectForRepaint(const RenderLayerModelObject* repaintContainer, LayoutRect&, bool fixed = false) const OVERRIDE;
-    virtual void repaintViewRectangle(const LayoutRect&, bool immediate = false) const;
+    void repaintViewRectangle(const LayoutRect&, bool immediate = false) const;
     // Repaint the view, and all composited layers that intersect the given absolute rectangle.
     // FIXME: ideally we'd never have to do this, if all repaints are container-relative.
-    virtual void repaintRectangleInViewAndCompositedLayers(const LayoutRect&, bool immediate = false);
+    void repaintRectangleInViewAndCompositedLayers(const LayoutRect&, bool immediate = false);
+    void repaintViewAndCompositedLayers();
 
     virtual void paint(PaintInfo&, const LayoutPoint&);
     virtual void paintBoxDecorations(PaintInfo&, const LayoutPoint&) OVERRIDE;