429168: fix for PdfJs regression

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 5be9c3a11fdfbe4d7659786217ff74dd83304bd0..a710fa9b91986b8ded53372e489f10b6a8ac6d60 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -1608,16 +1608,19 @@ class AllocationResult {
  public:
   // Implicit constructor from Object*.
   AllocationResult(Object* object)  // NOLINT
-      : object_(object),
-        retry_space_(INVALID_SPACE) {}
+      : object_(object) {
+    // AllocationResults can't return Smis, which are used to represent
+    // failure and the space to retry in.
+    CHECK(!object->IsSmi());
+  }
 
-  AllocationResult() : object_(NULL), retry_space_(INVALID_SPACE) {}
+  AllocationResult() : object_(Smi::FromInt(NEW_SPACE)) {}
 
   static inline AllocationResult Retry(AllocationSpace space = NEW_SPACE) {
     return AllocationResult(space);
   }
 
-  inline bool IsRetry() { return retry_space_ != INVALID_SPACE; }
+  inline bool IsRetry() { return object_->IsSmi(); }
 
   template <typename T>
   bool To(T** obj) {
@@ -1633,18 +1636,20 @@ class AllocationResult {
 
   AllocationSpace RetrySpace() {
     DCHECK(IsRetry());
-    return retry_space_;
+    return static_cast<AllocationSpace>(Smi::cast(object_)->value());
   }
 
  private:
   explicit AllocationResult(AllocationSpace space)
-      : object_(NULL), retry_space_(space) {}
+      : object_(Smi::FromInt(static_cast<int>(space))) {}
 
   Object* object_;
-  AllocationSpace retry_space_;
 };
 
 
+STATIC_ASSERT(sizeof(AllocationResult) == kPointerSize);
+
+
 class PagedSpace : public Space {
  public:
   // Creates a space with a maximum capacity, and an id.