Per-isolate v8::Locker and v8::Unlocker

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index ef4ddc0cda1216d72be8781ea15cc2c603dee7f5..d2807accf28f570f8c2e7778518ed69cde510d22 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -673,10 +673,11 @@ class ExternalReference BASE_EMBEDDED {
 
   // This lets you register a function that rewrites all external references.
   // Used by the ARM simulator to catch calls to external references.
-  static void set_redirector(ExternalReferenceRedirector* redirector) {
+  static void set_redirector(Isolate* isolate,
+                             ExternalReferenceRedirector* redirector) {
     // We can't stack them.
-    ASSERT(Isolate::Current()->external_reference_redirector() == NULL);
-    Isolate::Current()->set_external_reference_redirector(
+    ASSERT(isolate->external_reference_redirector() == NULL);
+    isolate->set_external_reference_redirector(
         reinterpret_cast<ExternalReferenceRedirectorPointer*>(redirector));
   }