[Isolates] Merge crankshaft (r5922 from bleeding_edge).

src/scopeinfo.h

Index: src/scopeinfo.h
diff --git a/src/scopeinfo.h b/src/scopeinfo.h
index 4ff88324df5ad4d681b2cd45f76ef9e40b3360da..cc9f8165a260eecf57260f644327c26e956285f3 100644
--- a/src/scopeinfo.h
+++ b/src/scopeinfo.h
@@ -109,9 +109,14 @@ class SerializedScopeInfo : public FixedArray {
     return reinterpret_cast<SerializedScopeInfo*>(object);
   }
 
-  // Does this scope call eval.
+  // Does this scope call eval?
   bool CallsEval();
 
+  // Does this scope have an arguments shadow?
+  bool HasArgumentsShadow() {
+    return StackSlotIndex(GetHeap()->arguments_shadow_symbol()) >= 0;
+  }
+
   // Return the number of stack slots for code.
   int NumberOfStackSlots();