Implement will-change-based GPU rasterization hint

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 198 matching lines @@
     m_graphicsLayer = createGraphicsLayer(m_owningLayer.compositingReasons());
 
 #if !OS(ANDROID)
     if (m_isMainFrameRenderViewLayer)
         m_graphicsLayer->contentLayer()->setDrawCheckerboardForMissingTiles(true);
 #endif
 
     updateOpacity(renderer()->style());
     updateTransform(renderer()->style());
     updateFilters(renderer()->style());
+    updateHasGpuRasterizationHint(renderer()->style());
 
     if (RuntimeEnabledFeatures::cssCompositingEnabled()) {
         updateLayerBlendMode(renderer()->style());
         updateIsRootForIsolatedGroup();
     }
 }
 
 void CompositedLayerMapping::destroyGraphicsLayers()
 {
     if (m_graphicsLayer)
@@ skipping 57 matching lines @@
 void CompositedLayerMapping::updateIsRootForIsolatedGroup()
 {
     bool isolate = m_owningLayer.shouldIsolateCompositedDescendants();
 
     // non stacking context layers should never isolate
     ASSERT(m_owningLayer.stackingNode()->isStackingContext() || !isolate);
 
     m_graphicsLayer->setIsRootForIsolatedGroup(isolate);
 }
 
+void CompositedLayerMapping::updateHasGpuRasterizationHint(const RenderStyle* style)
+{
+    m_graphicsLayer->setHasGpuRasterizationHint(style->hasWillChangeGpuRasterizationHint());
+}
+
 void CompositedLayerMapping::updateContentsOpaque()
 {
     // For non-root layers, background is always painted by the primary graphics layer.
     ASSERT(m_isMainFrameRenderViewLayer || !m_backgroundLayer);
     if (m_backgroundLayer) {
         m_graphicsLayer->setContentsOpaque(false);
         m_backgroundLayer->setContentsOpaque(m_owningLayer.backgroundIsKnownToBeOpaqueInRect(compositedBounds()));
     } else {
         m_graphicsLayer->setContentsOpaque(m_owningLayer.backgroundIsKnownToBeOpaqueInRect(compositedBounds()));
     }
@@ skipping 539 matching lines @@
 
     // We can't make this call in RenderLayerCompositor::allocateOrClearCompositedLayerMapping
     // since it depends on whether compAncestor draws content, which gets updated later.
     updateRequiresOwnBackingStoreForAncestorReasons(compAncestor);
 
     if (RuntimeEnabledFeatures::cssCompositingEnabled()) {
         updateLayerBlendMode(style);
         updateIsRootForIsolatedGroup();
     }
 
+    updateHasGpuRasterizationHint(renderer()->style());
     updateContentsRect();
     updateBackgroundColor();
     updateDrawsContent();
     updateContentsOpaque();
     updateAfterWidgetResize();
     updateRenderingContext();
     updateShouldFlattenTransform();
     updateChildrenTransform();
     registerScrollingLayers();
 
@@ skipping 1250 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore