Push version 2.5.7 to trunk....

src/execution.h

Index: src/execution.h
===================================================================
--- src/execution.h	(revision 5846)
+++ src/execution.h	(working copy)
@@ -189,6 +189,9 @@
   static uintptr_t climit() {
     return thread_local_.climit_;
   }
+  static uintptr_t real_climit() {
+    return thread_local_.real_climit_;
+  }
   static uintptr_t jslimit() {
     return thread_local_.jslimit_;
   }
@@ -313,29 +316,6 @@
   }
 };
 
-
-class GCExtension : public v8::Extension {
- public:
-  GCExtension() : v8::Extension("v8/gc", kSource) {}
-  virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
-      v8::Handle<v8::String> name);
-  static v8::Handle<v8::Value> GC(const v8::Arguments& args);
- private:
-  static const char* const kSource;
-};
-
-
-class ExternalizeStringExtension : public v8::Extension {
- public:
-  ExternalizeStringExtension() : v8::Extension("v8/externalize", kSource) {}
-  virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
-      v8::Handle<v8::String> name);
-  static v8::Handle<v8::Value> Externalize(const v8::Arguments& args);
-  static v8::Handle<v8::Value> IsAscii(const v8::Arguments& args);
- private:
-  static const char* const kSource;
-};
-
 } }  // namespace v8::internal
 
 #endif  // V8_EXECUTION_H_