[Do not commit] Experiment to test for cache misses during recursion

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/PrePaintTreeWalk.h"
 
 #include "core/dom/DocumentLifecycle.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/layout/LayoutMultiColumnSpannerPlaceholder.h"
@@ skipping 16 matching lines @@
   PaintPropertyTreeBuilderContext treeBuilderContext;
   PaintInvalidatorContext paintInvalidatorContext;
 
   // The ancestor in the PaintLayer tree which has overflow clip, or
   // is the root layer. Note that it is tree ancestor, not containing
   // block or stacking ancestor.
   PaintLayer* ancestorOverflowPaintLayer;
 };
 
 void PrePaintTreeWalk::walk(FrameView& rootFrame) {
+  //LOG(INFO) << "sizeOf(PrePaintTreeWalkContext): " << sizeof(PrePaintTreeWalkContext);
+  //LOG(INFO) << "sizeOf(PaintPropertyTreeBuilderContext): " << sizeof(PaintPropertyTreeBuilderContext);
+  //LOG(INFO) << "sizeOf(PaintInvalidatorContext): " << sizeof(PaintInvalidatorContext);
+  //LOG(INFO) << "sizeOf(PaintLayer*): " << sizeof(PaintLayer*);
+
   DCHECK(rootFrame.frame().document()->lifecycle().state() ==
          DocumentLifecycle::InPrePaint);
 
   PrePaintTreeWalkContext initialContext;
   initialContext.treeBuilderContext =
       m_propertyTreeBuilder.setupInitialContext();
   walk(rootFrame, initialContext);
   m_paintInvalidator.processPendingDelayedPaintInvalidations();
 }
 
 bool PrePaintTreeWalk::walk(FrameView& frameView,
-                            const PrePaintTreeWalkContext& parentContext) {
+                            PrePaintTreeWalkContext& context) {
   if (frameView.shouldThrottleRendering()) {
     // The walk was interrupted by throttled rendering so this subtree was not
     // fully updated.
     return false;
   }
 
-  PrePaintTreeWalkContext context(parentContext);
+  //PrePaintTreeWalkContext context(parentContext);
   m_propertyTreeBuilder.updateProperties(frameView, context.treeBuilderContext);
   m_paintInvalidator.invalidatePaintIfNeeded(frameView,
                                              context.paintInvalidatorContext);
 
   LayoutView* view = frameView.layoutView();
   bool descendantsFullyUpdated = view ? walk(*view, context) : true;
   if (descendantsFullyUpdated) {
 #if DCHECK_IS_ON()
     frameView.layoutView()->assertSubtreeClearedPaintInvalidationFlags();
 #endif
@@ skipping 26 matching lines @@
     paintLayer->updateLayerPosition();
   }
 
   if (object.hasOverflowClip() || (paintLayer && paintLayer->isRootLayer())) {
     DCHECK(paintLayer);
     context.ancestorOverflowPaintLayer = paintLayer;
   }
 }
 
 bool PrePaintTreeWalk::walk(const LayoutObject& object,
-                            const PrePaintTreeWalkContext& parentContext) {
-  PrePaintTreeWalkContext context(parentContext);
+                            PrePaintTreeWalkContext& context) {
+  //PrePaintTreeWalkContext context(parentContext);
 
   // This must happen before updateContextForBoxPosition, because the
   // latter reads some of the state computed uere.
   updateAuxiliaryObjectProperties(object, context);
 
   // Ensure the current context takes into account the box's position. This can
   // force a subtree update due to paint offset changes and must precede any
   // early out from the treewalk.
   LayoutPoint oldPaintOffset = object.paintOffset();
   m_propertyTreeBuilder.updateContextForBoxPosition(object,
@@ skipping 48 matching lines @@
 
   if (descendantsFullyUpdated) {
     // If descendants were not updated, do not clear flags. During the next
     // PrePaintTreeWalk, these flags will be used again.
     object.getMutableForPainting().clearPaintFlags();
   }
   return descendantsFullyUpdated;
 }
 
 }  // namespace blink