Replace RenderArena with PartitionAlloc.

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index 70f6a3e44e358bdcd4586651d1ec5fb1fe8afff1..fc70d00fa86cb4f1ddd6e5371f8185823fd3438f 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -67,6 +67,7 @@
 #include "core/page/animation/AnimationController.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/platform/HistogramSupport.h"
+#include "core/platform/Partitions.h"
 #include "core/platform/PlatformGestureEvent.h"
 #include "core/platform/PlatformMouseEvent.h"
 #include "core/platform/ScrollAnimator.h"
@@ -89,7 +90,6 @@
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/HitTestingTransformState.h"
 #include "core/rendering/OverlapTestRequestClient.h"
-#include "core/rendering/RenderArena.h"
 #include "core/rendering/RenderFlowThread.h"
 #include "core/rendering/RenderGeometryMap.h"
 #include "core/rendering/RenderInline.h"
@@ -1627,23 +1627,21 @@ void RenderLayer::beginTransparencyLayers(GraphicsContext* context, const Render
     }
 }
 
-void* RenderLayer::operator new(size_t sz, RenderArena* renderArena)
+#if ENABLE(PARTITION_ALLOC)
+void* RenderLayer::operator new(size_t sz)
 {
-    return renderArena->allocate(sz);
+    return partitionAlloc(Partitions::getRenderingPartition(), sz);
 }
 
-void RenderLayer::operator delete(void* ptr, size_t sz)
+void RenderLayer::operator delete(void* ptr)
 {
-    // Stash size where destroy can find it.
-    *(size_t *)ptr = sz;
+    partitionFree(ptr);
 }
+#endif
 
-void RenderLayer::destroy(RenderArena* renderArena)
+void RenderLayer::destroy()
 {
     delete this;
-
-    // Recover the size left there for us by operator delete and free the memory.
-    renderArena->free(*(size_t *)this, this);
 }
 
 void RenderLayer::addChild(RenderLayer* child, RenderLayer* beforeChild)