UMA stats instrumentation for Renderer.AcceleratedFixedRootBackground

Source/core/rendering/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 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 1175 matching lines @@
         frameViewDidScroll();
         updateOverflowControlsLayers();
 
 #if ENABLE(RUBBER_BANDING)
         if (m_layerForOverhangAreas)
             m_layerForOverhangAreas->setSize(frameView->frameRect().size());
 #endif
     }
 }
 
+enum AcceleratedFixedRootBackgroundHistogramBuckets {
+    ScrolledMainFrameBucket = 0,
+    ScrolledMainFrameWithAcceleratedFixedRootBackground = 1,
+    ScrolledMainFrameWithUnacceleratedFixedRootBackground = 2,
+    AcceleratedFixedRootBackgroundHistogramMax = 3
+};
+
 void RenderLayerCompositor::frameViewDidScroll()
 {
     FrameView* frameView = m_renderView->frameView();
     IntPoint scrollPosition = frameView->scrollPosition();
 
     if (!m_scrollLayer)
         return;
 
     bool scrollingCoordinatorHandlesOffset = false;
     if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator()) {
         if (Settings* settings = m_renderView->document().settings()) {
             if (isMainFrame() || settings->compositedScrollingForFramesEnabled())
                 scrollingCoordinatorHandlesOffset = scrollingCoordinator->scrollableAreaScrollLayerDidChange(frameView);
         }
     }
 
     // Scroll position = scroll minimum + scroll offset. Adjust the layer's
     // position to handle whatever the scroll coordinator isn't handling.
     // The minimum scroll position is non-zero for RTL pages with overflow.
     if (scrollingCoordinatorHandlesOffset)
         m_scrollLayer->setPosition(-frameView->minimumScrollPosition());
     else
         m_scrollLayer->setPosition(-scrollPosition);
+
+
+    HistogramSupport::histogramEnumeration("Renderer.AcceleratedFixedRootBackground",
+        ScrolledMainFrameBucket,
+        AcceleratedFixedRootBackgroundHistogramMax);
+
+    if (!m_renderView->rootBackgroundIsEntirelyFixed())

[hartmanng, 2013/09/09 14:31:26]

I remember you mentioned that pages can have partially-fixed backgrounds - are
you sure "entirely fixed" is the only thing you want to measure?

+        return;
+
+    HistogramSupport::histogramEnumeration("Renderer.AcceleratedFixedRootBackground",
+        !!fixedRootBackgroundLayer()
+            ? ScrolledMainFrameWithAcceleratedFixedRootBackground
+            : ScrolledMainFrameWithUnacceleratedFixedRootBackground,
+        AcceleratedFixedRootBackgroundHistogramMax);
 }
 
 void RenderLayerCompositor::frameViewDidLayout()
 {
 }
 
 void RenderLayerCompositor::rootFixedBackgroundsChanged()
 {
     if (!supportsFixedRootBackgroundCompositing())
         return;
@@ skipping 1505 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "Frame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore