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 71c1ebf9c1a3dbc5742c8849ebd69fa57678308f..80362fe7d3d741e8487f7139b9edb2b11d40e937 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -710,8 +710,15 @@ void RenderLayer::setHasVisibleContent()
         return;
     }
 
-    m_visibleContentStatusDirty = false;
     m_hasVisibleContent = true;
+    m_visibleContentStatusDirty = false;
+
+    {
+        DisableCompositingQueryAsserts disabler;

[ojan, 2014/03/05 18:29:51]

Are there tests that you know hit this? It'd be nice to have a comment pointing
to one for the person who tries to fix this.

Also, should there be a FIXME here since you say this can be removed once we
untangle the recursive tree walk inside updateGraphicsLayerGeometry.?

[abarth-chromium, 2014/03/05 23:12:19]

I haven't tried, but I'm sure it's hit by many tests.
Will do.

+        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.
@@ -875,6 +882,10 @@ void RenderLayer::updateDescendantDependentFlags()
             }
         }
         m_visibleContentStatusDirty = false;
+
+        DisableCompositingQueryAsserts disabler;
+        if (RenderLayer* compositingLayer = enclosingCompositingLayer())
+            compositingLayer->compositedLayerMapping()->setNeedsGeometryUpdate();

[ojan, 2014/03/05 18:29:51]

Technically, you only need to do this if m_hasVisibleContent changed values,
right?

[abarth-chromium, 2014/03/05 23:12:19]

That's right.  I'll add that branch.

     }
 }
 
@@ -3507,6 +3518,7 @@ CompositedLayerMappingPtr RenderLayer::ensureCompositedLayerMapping()
 {
     if (!m_compositedLayerMapping) {
         m_compositedLayerMapping = adoptPtr(new CompositedLayerMapping(this));
+        m_compositedLayerMapping->setNeedsGeometryUpdate();
 
         updateOrRemoveFilterEffectRenderer();
 
@@ -3518,6 +3530,9 @@ CompositedLayerMappingPtr RenderLayer::ensureCompositedLayerMapping()
 
 void RenderLayer::clearCompositedLayerMapping(bool layerBeingDestroyed)
 {
+    if (!layerBeingDestroyed)
+        m_compositedLayerMapping->setNeedsGeometryUpdate();
+
     m_compositedLayerMapping.clear();
 
     if (!layerBeingDestroyed)
@@ -3873,6 +3888,9 @@ 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);