Update V8 to r6768 as required by WebKit r78450

Change-Id: Ib8868ff7147a76547a8d1d85f257ebe8546a3d3f
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 76f29f0..0d0e37f 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -59,6 +59,7 @@
   V(GenericUnaryOp)                      \
   V(RevertToNumber)                      \
   V(ToBoolean)                           \
+  V(ToNumber)                            \
   V(CounterOp)                           \
   V(ArgumentsAccess)                     \
   V(RegExpExec)                          \
@@ -74,7 +75,8 @@
   V(GetProperty)               \
   V(SetProperty)               \
   V(InvokeBuiltin)             \
-  V(RegExpCEntry)
+  V(RegExpCEntry)              \
+  V(DirectCEntry)
 #else
 #define CODE_STUB_LIST_ARM(V)
 #endif
@@ -260,6 +262,19 @@
 };
 
 
+class ToNumberStub: public CodeStub {
+ public:
+  ToNumberStub() { }
+
+  void Generate(MacroAssembler* masm);
+
+ private:
+  Major MajorKey() { return ToNumber; }
+  int MinorKey() { return 0; }
+  const char* GetName() { return "ToNumberStub"; }
+};
+
+
 class FastNewClosureStub : public CodeStub {
  public:
   void Generate(MacroAssembler* masm);
@@ -599,8 +614,7 @@
                     Label* throw_termination_exception,
                     Label* throw_out_of_memory_exception,
                     bool do_gc,
-                    bool always_allocate_scope,
-                    int alignment_skew = 0);
+                    bool always_allocate_scope);
   void GenerateThrowTOS(MacroAssembler* masm);
   void GenerateThrowUncatchable(MacroAssembler* masm,
                                 UncatchableExceptionType type);