[objects.h splitting] Move ObjectVisitor.

There was a helpful TODO telling where it should live.

BUG=v8:5402,v8:6921

Change-Id: Id9022c72c9e7de8d76ea0db964217b766299195d
Reviewed-on: https://chromium-review.googlesource.com/718337Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48524}

src/heap/objects-visiting.h

@@ -11,6 +11,7 @@
 #include "src/objects.h"
 #include "src/objects/hash-table.h"
 #include "src/objects/string.h"
+#include "src/visitors.h"
 
 namespace v8 {
 namespace internal {

src/objects.h

@@ -7050,51 +7050,6 @@ class SourcePositionTableWithFrameCache : public Tuple2 {
   DISALLOW_IMPLICIT_CONSTRUCTORS(SourcePositionTableWithFrameCache);
 };
 
-// Abstract base class for visiting, and optionally modifying, the
-// pointers contained in Objects. Used in GC and serialization/deserialization.
-// TODO(ulan): move to src/visitors.h
-class ObjectVisitor BASE_EMBEDDED {
- public:
-  virtual ~ObjectVisitor() {}
-
-  // Visits a contiguous arrays of pointers in the half-open range
-  // [start, end). Any or all of the values may be modified on return.
-  virtual void VisitPointers(HeapObject* host, Object** start,
-                             Object** end) = 0;
-
-  // Handy shorthand for visiting a single pointer.
-  virtual void VisitPointer(HeapObject* host, Object** p) {
-    VisitPointers(host, p, p + 1);
-  }
-
-  // Visit weak next_code_link in Code object.
-  virtual void VisitNextCodeLink(Code* host, Object** p) {
-    VisitPointers(host, p, p + 1);
-  }
-
-  // To allow lazy clearing of inline caches the visitor has
-  // a rich interface for iterating over Code objects..
-
-  // Visits a code target in the instruction stream.
-  virtual void VisitCodeTarget(Code* host, RelocInfo* rinfo);
-
-  // Visits a runtime entry in the instruction stream.
-  virtual void VisitRuntimeEntry(Code* host, RelocInfo* rinfo) {}
-
-  // Visit pointer embedded into a code object.
-  virtual void VisitEmbeddedPointer(Code* host, RelocInfo* rinfo);
-
-  // Visits an external reference embedded into a code object.
-  virtual void VisitExternalReference(Code* host, RelocInfo* rinfo) {}
-
-  // Visits an external reference.
-  virtual void VisitExternalReference(Foreign* host, Address* p) {}
-
-  // Visits an (encoded) internal reference.
-  virtual void VisitInternalReference(Code* host, RelocInfo* rinfo) {}
-};
-
-
 // BooleanBit is a helper class for setting and getting a bit in an integer.
 class BooleanBit : public AllStatic {
  public:

src/visitors.cc

@@ -4,6 +4,8 @@
 
 #include "src/visitors.h"
 
+#include "src/objects.h"
+
 namespace v8 {
 namespace internal {
 
@@ -18,5 +20,9 @@ const char* const VisitorSynchronization::kTagNames
     [VisitorSynchronization::kNumberOfSyncTags] = {ROOT_ID_LIST(DECLARE_TAG)};
 #undef DECLARE_TAG
 
+void ObjectVisitor::VisitNextCodeLink(Code* host, Object** p) {
+  VisitPointers(host, p, p + 1);
+}
+
 }  // namespace internal
 }  // namespace v8

src/visitors.h

@@ -75,6 +75,47 @@ class RootVisitor BASE_EMBEDDED {
   virtual void Synchronize(VisitorSynchronization::SyncTag tag) {}
 };
 
+// Abstract base class for visiting, and optionally modifying, the
+// pointers contained in Objects. Used in GC and serialization/deserialization.
+class ObjectVisitor BASE_EMBEDDED {
+ public:
+  virtual ~ObjectVisitor() {}
+
+  // Visits a contiguous arrays of pointers in the half-open range
+  // [start, end). Any or all of the values may be modified on return.
+  virtual void VisitPointers(HeapObject* host, Object** start,
+                             Object** end) = 0;
+
+  // Handy shorthand for visiting a single pointer.
+  virtual void VisitPointer(HeapObject* host, Object** p) {
+    VisitPointers(host, p, p + 1);
+  }
+
+  // Visit weak next_code_link in Code object.
+  virtual void VisitNextCodeLink(Code* host, Object** p);
+
+  // To allow lazy clearing of inline caches the visitor has
+  // a rich interface for iterating over Code objects..
+
+  // Visits a code target in the instruction stream.
+  virtual void VisitCodeTarget(Code* host, RelocInfo* rinfo);
+
+  // Visits a runtime entry in the instruction stream.
+  virtual void VisitRuntimeEntry(Code* host, RelocInfo* rinfo) {}
+
+  // Visit pointer embedded into a code object.
+  virtual void VisitEmbeddedPointer(Code* host, RelocInfo* rinfo);
+
+  // Visits an external reference embedded into a code object.
+  virtual void VisitExternalReference(Code* host, RelocInfo* rinfo) {}
+
+  // Visits an external reference.
+  virtual void VisitExternalReference(Foreign* host, Address* p) {}
+
+  // Visits an (encoded) internal reference.
+  virtual void VisitInternalReference(Code* host, RelocInfo* rinfo) {}
+};
+
 }  // namespace internal
 }  // namespace v8