Update V8 to r3431 as required by WebKit r51976.

Change-Id: I567392c3f8c0a0d5201a4249611ac4ccf468cd5b
diff --git a/src/factory.cc b/src/factory.cc
index 32b69db..83775ef 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -106,10 +106,10 @@
 }
 
 
-Handle<String> Factory::NewStringSlice(Handle<String> str,
-                                       int begin,
-                                       int end) {
-  CALL_HEAP_FUNCTION(str->Slice(begin, end), String);
+Handle<String> Factory::NewSubString(Handle<String> str,
+                                     int begin,
+                                     int end) {
+  CALL_HEAP_FUNCTION(str->SubString(begin, end), String);
 }
 
 
@@ -189,7 +189,7 @@
   script->set_compilation_type(Smi::FromInt(Script::COMPILATION_TYPE_HOST));
   script->set_wrapper(*wrapper);
   script->set_line_ends(Heap::undefined_value());
-  script->set_eval_from_function(Heap::undefined_value());
+  script->set_eval_from_shared(Heap::undefined_value());
   script->set_eval_from_instructions_offset(Smi::FromInt(0));
 
   return script;