Valgrind cleanliness, part 5: Delete extensions on exit.

src/api.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 128 matching lines @@
  private:
   v8::internal::Address addr_;
 };
 
 
 
 class RegisteredExtension {
  public:
   explicit RegisteredExtension(Extension* extension);
   static void Register(RegisteredExtension* that);
+  static void UnregisterAll();
   Extension* extension() { return extension_; }
   RegisteredExtension* next() { return next_; }
   RegisteredExtension* next_auto() { return next_auto_; }
   static RegisteredExtension* first_extension() { return first_extension_; }
  private:
   Extension* extension_;
   RegisteredExtension* next_;
   RegisteredExtension* next_auto_;
   static RegisteredExtension* first_extension_;
 };
@@ skipping 400 matching lines @@
     stress_type_ = stress_type;
   }
 
  private:
   static v8::Testing::StressType stress_type_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_API_H_