remove this == null

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 9e28d012fb71b28a93606ad1e6d08c596f323f18..21a509429efb92e9ff58cac3a8ad26f7f5be0256 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -3365,8 +3365,9 @@ AllocationResult Heap::AllocateCode(int object_size,
 
   result->set_map_no_write_barrier(code_map());
   Code* code = Code::cast(result);
-  ASSERT(!isolate_->code_range()->exists() ||
-      isolate_->code_range()->contains(code->address()));
+  ASSERT(isolate_->code_range() == NULL ||
+         !isolate_->code_range()->valid() ||
+         isolate_->code_range()->contains(code->address()));
   code->set_gc_metadata(Smi::FromInt(0));
   code->set_ic_age(global_ic_age_);
   return code;
@@ -3407,8 +3408,9 @@ AllocationResult Heap::CopyCode(Code* code) {
   new_code->set_constant_pool(new_constant_pool);
 
   // Relocate the copy.
-  ASSERT(!isolate_->code_range()->exists() ||
-      isolate_->code_range()->contains(code->address()));
+  ASSERT(isolate_->code_range() == NULL ||
+         !isolate_->code_range()->valid() ||
+         isolate_->code_range()->contains(code->address()));
   new_code->Relocate(new_addr - old_addr);
   return new_code;
 }
@@ -3471,8 +3473,9 @@ AllocationResult Heap::CopyCode(Code* code, Vector<byte> reloc_info) {
             static_cast<size_t>(reloc_info.length()));
 
   // Relocate the copy.
-  ASSERT(!isolate_->code_range()->exists() ||
-      isolate_->code_range()->contains(code->address()));
+  ASSERT(isolate_->code_range() == NULL ||
+         !isolate_->code_range()->valid() ||
+         isolate_->code_range()->contains(code->address()));
   new_code->Relocate(new_addr - old_addr);
 
 #ifdef VERIFY_HEAP