Make sure the heap is in consistent state when calling allocation observers.

src/heap/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/spaces.h"
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/base/platform/semaphore.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 2426 matching lines @@
   // if it is big enough.
   owner_->Free(owner_->top(), old_linear_size);
   owner_->SetTopAndLimit(nullptr, nullptr);
 
   owner_->heap()->incremental_marking()->OldSpaceStep(size_in_bytes -
                                                       old_linear_size);
 
   int new_node_size = 0;
   FreeSpace* new_node = FindNodeFor(size_in_bytes, &new_node_size);
   if (new_node == nullptr) return nullptr;
-  owner_->AllocationStep(new_node->address(), size_in_bytes);
 
   int bytes_left = new_node_size - size_in_bytes;
   DCHECK(bytes_left >= 0);
 
 #ifdef DEBUG
   for (int i = 0; i < size_in_bytes / kPointerSize; i++) {
     reinterpret_cast<Object**>(new_node->address())[i] =
         Smi::FromInt(kCodeZapValue);
   }
 #endif
@@ skipping 25 matching lines @@
                  new_node_size - size_in_bytes - linear_size);
     owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
                            new_node->address() + size_in_bytes + linear_size);
   } else if (bytes_left > 0) {
     // Normally we give the rest of the node to the allocator as its new
     // linear allocation area.
     owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
                            new_node->address() + new_node_size);
   }
 
+  owner_->AllocationStep(new_node->address(), size_in_bytes);
+
   return new_node;
 }
 
 intptr_t FreeList::EvictFreeListItems(Page* page) {
   intptr_t sum = 0;
   page->ForAllFreeListCategories(
       [this, &sum, page](FreeListCategory* category) {
         DCHECK_EQ(this, category->owner());
         sum += category->available();
         RemoveCategory(category);
@@ skipping 717 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8