Update V8 to r6387 as required by WebKit r76408

Change-Id: Icfc5385b0996bd592f8b1ac8cbb44767ee09f1f6
diff --git a/src/frames.h b/src/frames.h
index 778f9d2..5378709 100644
--- a/src/frames.h
+++ b/src/frames.h
@@ -28,6 +28,8 @@
 #ifndef V8_FRAMES_H_
 #define V8_FRAMES_H_
 
+#include "safepoint-table.h"
+
 namespace v8 {
 namespace internal {
 
@@ -51,7 +53,7 @@
   struct PcToCodeCacheEntry {
     Address pc;
     Code* code;
-    uint8_t* safepoint_entry;
+    SafepointEntry safepoint_entry;
   };
 
   static PcToCodeCacheEntry* cache(int index) {
@@ -208,7 +210,7 @@
   // safepoint entry and the number of stack slots. The pc must be at
   // a safepoint.
   static Code* GetSafepointData(Address pc,
-                                uint8_t** safepoint_entry,
+                                SafepointEntry* safepoint_entry,
                                 unsigned* stack_slots);
 
   virtual void Iterate(ObjectVisitor* v) const = 0;