Soft fail for invalid cache data.

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index 822151d64a9934cd79b229bdcd5325f2bef3e229..c8073feda90dd2875a8783ec829cc2feab5ac207 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -39,6 +39,9 @@ class ScriptData {
 
   const byte* data() const { return data_; }
   int length() const { return length_; }
+  bool rejected() const { return rejected_; }
+
+  void Reject() { rejected_ = true; }
 
   void AcquireDataOwnership() {
     DCHECK(!owns_data_);
@@ -51,7 +54,8 @@ class ScriptData {
   }
 
  private:
-  bool owns_data_;
+  bool owns_data_ : 1;
+  bool rejected_ : 1;
   const byte* data_;
   int length_;