Implement will-change-based GPU rasterization hint

Source/platform/graphics/GraphicsLayer.cpp

Index: Source/platform/graphics/GraphicsLayer.cpp
diff --git a/Source/platform/graphics/GraphicsLayer.cpp b/Source/platform/graphics/GraphicsLayer.cpp
index a6410402f30b9cfd1538208f917dec9eb3e2d8f0..310f49aa6fdae87b1f5245f47aba0d33c7c9498d 100644
--- a/Source/platform/graphics/GraphicsLayer.cpp
+++ b/Source/platform/graphics/GraphicsLayer.cpp
@@ -89,6 +89,7 @@ GraphicsLayer::GraphicsLayer(GraphicsLayerClient* client)
     , m_drawsContent(false)
     , m_contentsVisible(true)
     , m_isRootForIsolatedGroup(false)
+    , m_hasGpuRasterizationHint(false)
     , m_hasScrollParent(false)
     , m_hasClipParent(false)
     , m_paintingPhase(GraphicsLayerPaintAllWithOverflowClip)
@@ -607,6 +608,11 @@ void GraphicsLayer::dumpProperties(TextStream& ts, int indent, LayerTreeFlags fl
         ts << "(contentsVisible " << m_contentsVisible << ")\n";
     }
 
+    if (m_hasGpuRasterizationHint) {
+        writeIndent(ts, indent + 1);
+        ts << "(hasGpuRasterizationHint " << m_hasGpuRasterizationHint << ")\n";
+    }
+
     if (!m_backfaceVisibility) {
         writeIndent(ts, indent + 1);
         ts << "(backfaceVisibility " << (m_backfaceVisibility ? "visible" : "hidden") << ")\n";
@@ -946,6 +952,12 @@ void GraphicsLayer::setIsRootForIsolatedGroup(bool isolated)
     platformLayer()->setIsRootForIsolatedGroup(isolated);
 }
 
+void GraphicsLayer::setHasGpuRasterizationHint(bool hasHint)
+{
+    m_hasGpuRasterizationHint = hasHint;
+    m_layer->setHasGpuRasterizationHint(hasHint);
+}
+
 void GraphicsLayer::setContentsNeedsDisplay()
 {
     if (WebLayer* contentsLayer = contentsLayerIfRegistered()) {