WIP - compositor worker mega patch.

third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.cpp

 // Copyright 2014 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/layout/compositing/CompositingReasonFinder.h"
 
 #include "core/CSSPropertyNames.h"
 #include "core/dom/Document.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
@@ skipping 81 matching lines @@
 
     if (style.hasInlineTransform())
         reasons |= CompositingReasonInlineTransform;
 
     if (style.transformStyle3D() == TransformStyle3DPreserve3D)
         reasons |= CompositingReasonPreserve3DWith3DDescendants;
 
     if (style.hasPerspective())
         reasons |= CompositingReasonPerspectiveWith3DDescendants;
 
-    if (style.hasCompositorProxy())
+    if (style.hasCompositorProxy()) {
+        TRACE_EVENT0("compositor-worker", "CompositingReasonFinder -- has compositor proxy");
         reasons |= CompositingReasonCompositorProxy;
+    }
 
     // If the implementation of createsGroup changes, we need to be aware of that in this part of code.
     ASSERT((layoutObject->isTransparent() || layoutObject->hasMask() || layoutObject->hasFilter() || style.hasBlendMode()) == layoutObject->createsGroup());
 
     if (style.hasMask())
         reasons |= CompositingReasonMaskWithCompositedDescendants;
 
     if (style.hasFilter())
         reasons |= CompositingReasonFilterWithCompositedDescendants;
 
@@ skipping 65 matching lines @@
 bool CompositingReasonFinder::requiresCompositingForPositionFixed(const PaintLayer* layer) const
 {
     if (!(m_compositingTriggers & ViewportConstrainedPositionedTrigger))
         return false;
     // Don't promote fixed position elements that are descendants of a non-view container, e.g. transformed elements.
     // They will stay fixed wrt the container rather than the enclosing frame.
     return layer->scrollsWithViewport() && m_layoutView.frameView()->isScrollable();
 }
 
 }