[heap] Invoke incremental marking step before allocation.

src/heap/spaces.cc

Index: src/heap/spaces.cc
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index 17d2a70144b271c767270d2c87dbef185dec6042..2719fe35585d2dae2d64172d2a4e075661729036 100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -2581,6 +2581,15 @@ HeapObject* FreeList::Allocate(size_t size_in_bytes) {
 
   owner_->heap()->StartIncrementalMarkingIfAllocationLimitIsReached(
       Heap::kNoGCFlags, kNoGCCallbackFlags);
+  // We cannot place incremental marking step in an AllocationObserver because
+  // 1) incremental marking step can change linear allocation area.
+  // 2) allocation observers are called after allocation.
+  // 3) allocation folding assumes that the newly allocated object immediately
+  //    precedes the linear allocation area.
+  // See crbug.com/659165.
+  owner_->heap()
+      ->incremental_marking()
+      ->AdvanceIncrementalMarkingOnAllocation();
 
   size_t new_node_size = 0;
   FreeSpace* new_node = FindNodeFor(size_in_bytes, &new_node_size);
@@ -3010,6 +3019,8 @@ AllocationResult LargeObjectSpace::AllocateRaw(int object_size,
 
   heap()->StartIncrementalMarkingIfAllocationLimitIsReached(Heap::kNoGCFlags,
                                                             kNoGCCallbackFlags);
+  heap()->incremental_marking()->AdvanceIncrementalMarkingOnAllocation();
+
   AllocationStep(object->address(), object_size);
 
   if (heap()->incremental_marking()->black_allocation()) {