[Invalidation Tracking] Add trace events for compositor based invalidations

Source/core/rendering/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 590 matching lines @@
     // offset to be.
     for (size_t i = 0; i < layers.size(); ++i) {
         LayoutPoint offsetFromTransformedAncestorForSquashedLayer = layers[i].renderLayer->computeOffsetFromTransformedAncestor();
         LayoutSize offsetFromSquashLayerOrigin = (offsetFromTransformedAncestorForSquashedLayer - referenceOffsetFromTransformedAncestor) - squashLayerOriginInOwningLayerSpace;
 
         // It is ok to issue paint invalidation here, because all of the geometry needed to correctly invalidate paint is computed by this point.
         IntSize newOffsetFromRenderer = -IntSize(offsetFromSquashLayerOrigin.width().round(), offsetFromSquashLayerOrigin.height().round());
         LayoutSize subpixelAccumulation = offsetFromSquashLayerOrigin + newOffsetFromRenderer;
         if (layers[i].offsetFromRendererSet && layers[i].offsetFromRenderer != newOffsetFromRenderer) {
             layers[i].renderLayer->paintInvalidator().paintInvalidationIncludingNonCompositingDescendants();
+
+            TRACE_LAYER_INVALIDATION(layers[i].renderLayer, InspectorLayerInvalidationTrackingEvent::SquashingLayerGeometryWasUpdated);
             layersNeedingPaintInvalidation.append(layers[i].renderLayer);
         }
         layers[i].offsetFromRenderer = newOffsetFromRenderer;
         layers[i].offsetFromRendererSet = true;
 
         layers[i].renderLayer->setSubpixelAccumulation(subpixelAccumulation);
     }
 
     squashingLayer->setPosition(squashLayerBounds.location());
     squashingLayer->setSize(squashLayerBounds.size());
@@ skipping 1730 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink