Replace RenderArena with PartitionAlloc.

Source/core/platform/Partitions.cpp

Index: Source/core/platform/Partitions.cpp
diff --git a/Source/core/loader/UniqueIdentifier.cpp b/Source/core/platform/Partitions.cpp
similarity index 81%
copy from Source/core/loader/UniqueIdentifier.cpp
copy to Source/core/platform/Partitions.cpp
index 0ad56563e3e214a67acd8c53decb085ad4250cb9..f7d8ac1cc9bf15909400eade6c955038a58b3066 100644
--- a/Source/core/loader/UniqueIdentifier.cpp
+++ b/Source/core/platform/Partitions.cpp
@@ -28,17 +28,25 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+
 #include "config.h"
-#include "core/loader/UniqueIdentifier.h"
+#include "core/platform/Partitions.h"
 
 namespace WebCore {
 
-static unsigned long s_uniqueIdentifier = 0;
+PartitionRoot Partitions::m_objectModelRoot;
+PartitionRoot Partitions::m_renderingRoot;
 
-unsigned long createUniqueIdentifier()
+void Partitions::init()
 {
-    return ++s_uniqueIdentifier;
+    partitionAllocInit(&m_objectModelRoot);
+    partitionAllocInit(&m_renderingRoot);
 }
 
-} // namespace WebCore
+void Partitions::shutdown()
+{
+    partitionAllocShutdown(&m_objectModelRoot);
+    partitionAllocShutdown(&m_renderingRoot);
+}
 
+} // namespace WebCore