Refactor BasicBlock, no inheritance from GenericNode

src/compiler/scheduler.h

Index: src/compiler/scheduler.h
diff --git a/src/compiler/scheduler.h b/src/compiler/scheduler.h
index b21662f60cc57429fbb812b3ef12f6d97e349ec0..854e27d4203ca3fe620e38da4accc30de3f0baf0 100644
--- a/src/compiler/scheduler.h
+++ b/src/compiler/scheduler.h
@@ -66,10 +66,11 @@ class Scheduler {
   Placement GetPlacement(Node* node);
 
   int GetRPONumber(BasicBlock* block) {
-    DCHECK(block->rpo_number_ >= 0 &&
-           block->rpo_number_ < static_cast<int>(schedule_->rpo_order_.size()));
-    DCHECK(schedule_->rpo_order_[block->rpo_number_] == block);
-    return block->rpo_number_;
+    DCHECK(block->rpo_number() >= 0 &&
+           block->rpo_number() <
+               static_cast<int>(schedule_->rpo_order_.size()));
+    DCHECK(schedule_->rpo_order_[block->rpo_number()] == block);
+    return block->rpo_number();
   }
 
   void GenerateImmediateDominatorTree();