Reduce compositing update in Silk's toggle_drawer by 20%

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 42f61fba0ee347a78f79d491e8b285c7e06b5213..b8c06335b466401b9dfd65c2b223bb1e56e04d7b 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -710,8 +710,17 @@ void RenderLayer::setHasVisibleContent()
         return;
     }
 
-    m_visibleContentStatusDirty = false;
     m_hasVisibleContent = true;
+    m_visibleContentStatusDirty = false;
+
+    {
+        // FIXME: We can remove this code once we remove the recursive tree
+        // walk inside updateGraphicsLayerGeometry.
+        DisableCompositingQueryAsserts disabler;
+        if (RenderLayer* compositingLayer = enclosingCompositingLayer())
+            compositingLayer->compositedLayerMapping()->setNeedsGeometryUpdate();
+    }
+
     repainter().computeRepaintRects(renderer()->containerForRepaint());
     if (!m_stackingNode->isNormalFlowOnly()) {
         // We don't collect invisible layers in z-order lists if we are not in compositing mode.
@@ -848,6 +857,7 @@ void RenderLayer::updateDescendantDependentFlags()
     }
 
     if (m_visibleContentStatusDirty) {
+        bool previouslyHasVisibleCOntent = m_hasVisibleContent;
         if (renderer()->style()->visibility() == VISIBLE)
             m_hasVisibleContent = true;
         else {
@@ -875,6 +885,14 @@ void RenderLayer::updateDescendantDependentFlags()
             }
         }
         m_visibleContentStatusDirty = false;
+
+        // FIXME: We can remove this code once we remove the recursive tree
+        // walk inside updateGraphicsLayerGeometry.
+        if (hasVisibleContent() != previouslyHasVisibleCOntent) {
+            DisableCompositingQueryAsserts disabler;
+            if (RenderLayer* compositingLayer = enclosingCompositingLayer())
+                compositingLayer->compositedLayerMapping()->setNeedsGeometryUpdate();
+        }
     }
 }
 
@@ -3511,6 +3529,7 @@ CompositedLayerMappingPtr RenderLayer::ensureCompositedLayerMapping()
 {
     if (!m_compositedLayerMapping) {
         m_compositedLayerMapping = adoptPtr(new CompositedLayerMapping(this));
+        m_compositedLayerMapping->setNeedsGeometryUpdate();
 
         updateOrRemoveFilterEffectRenderer();
 
@@ -3522,6 +3541,9 @@ CompositedLayerMappingPtr RenderLayer::ensureCompositedLayerMapping()
 
 void RenderLayer::clearCompositedLayerMapping(bool layerBeingDestroyed)
 {
+    if (!layerBeingDestroyed)
+        m_compositedLayerMapping->setNeedsGeometryUpdate();
+
     m_compositedLayerMapping.clear();
 
     if (!layerBeingDestroyed)
@@ -3877,6 +3899,9 @@ void RenderLayer::styleChanged(StyleDifference diff, const RenderStyle* oldStyle
     // https://code.google.com/p/chromium/issues/detail?id=343756
     DisableCompositingQueryAsserts disabler;
 
+    if (RenderLayer* compositingLayer = enclosingCompositingLayer())
+        compositingLayer->compositedLayerMapping()->setNeedsGeometryUpdate();
+
     const RenderStyle* newStyle = renderer()->style();
 
     compositor()->updateLayerCompositingState(this, RenderLayerCompositor::UseChickenEggHacks);