1 files changed, 16 insertions, 1 deletions
diff --git a/Source/WebCore/bindings/js/JSMainThreadExecState.h b/Source/WebCore/bindings/js/JSMainThreadExecState.h
index 55b820324..5e4c4e2dc 100644
--- a/Source/WebCore/bindings/js/JSMainThreadExecState.h
+++ b/Source/WebCore/bindings/js/JSMainThreadExecState.h
@@ -92,19 +92,34 @@ protected:
         ASSERT(isMainThread());
         s_mainThreadState = exec;
     };
-    
+
     ~JSMainThreadExecState()
     {
         ASSERT(isMainThread());
+
+#if ENABLE(MUTATION_OBSERVERS)
+        bool didExitJavaScript = s_mainThreadState && !m_previousState;
+#endif
+
         s_mainThreadState = m_previousState;
+
+#if ENABLE(MUTATION_OBSERVERS)
+        if (didExitJavaScript)
+            didLeaveScriptContext();
+#endif
     }
 
 private:
     static JSC::ExecState* s_mainThreadState;
     JSC::ExecState* m_previousState;
+
+#if ENABLE(MUTATION_OBSERVERS)
+    static void didLeaveScriptContext();
+#endif
 };
 
 // Null state prevents origin security checks.
+// Used by non-JavaScript bindings (ObjC, GObject).
 class JSMainThreadNullState : private JSMainThreadExecState {
 public:
     explicit JSMainThreadNullState() : JSMainThreadExecState(0) {};