diff --git a/include/v8.h b/include/v8.h
index 5b5dabe..24b4cbe 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -134,6 +134,7 @@
 
 class Arguments;
 class Object;
+class Heap;
 class Top;
 
 }
@@ -513,6 +514,7 @@
 class V8EXPORT ScriptData {  // NOLINT
  public:
   virtual ~ScriptData() { }
+
   /**
    * Pre-compiles the specified script (context-independent).
    *
@@ -522,6 +524,16 @@
   static ScriptData* PreCompile(const char* input, int length);
 
   /**
+   * Pre-compiles the specified script (context-independent).
+   *
+   * NOTE: Pre-compilation using this method cannot happen on another thread
+   * without using Lockers.
+   *
+   * \param source Script source code.
+   */
+  static ScriptData* PreCompile(Handle<String> source);
+
+  /**
    * Load previous pre-compilation data.
    *
    * \param data Pointer to data returned by a call to Data() of a previous
@@ -1026,12 +1038,24 @@
   class V8EXPORT ExternalStringResourceBase {
    public:
     virtual ~ExternalStringResourceBase() {}
+
    protected:
     ExternalStringResourceBase() {}
+
+    /**
+     * Internally V8 will call this Dispose method when the external string
+     * resource is no longer needed. The default implementation will use the
+     * delete operator. This method can be overridden in subclasses to
+     * control how allocated external string resources are disposed.
+     */
+    virtual void Dispose() { delete this; }
+
    private:
     // Disallow copying and assigning.
     ExternalStringResourceBase(const ExternalStringResourceBase&);
     void operator=(const ExternalStringResourceBase&);
+
+    friend class v8::internal::Heap;
   };
 
   /**
@@ -1048,10 +1072,17 @@
      * buffer.
      */
     virtual ~ExternalStringResource() {}
-    /** The string data from the underlying buffer.*/
+
+    /**
+     * The string data from the underlying buffer.
+     */
     virtual const uint16_t* data() const = 0;
-    /** The length of the string. That is, the number of two-byte characters.*/
+
+    /**
+     * The length of the string. That is, the number of two-byte characters.
+     */
     virtual size_t length() const = 0;
+
    protected:
     ExternalStringResource() {}
   };
@@ -1122,11 +1153,11 @@
 
   /**
    * Creates a new external string using the data defined in the given
-   * resource. The resource is deleted when the external string is no
-   * longer live on V8's heap. The caller of this function should not
-   * delete or modify the resource. Neither should the underlying buffer be
-   * deallocated or modified except through the destructor of the
-   * external string resource.
+   * resource. When the external string is no longer live on V8's heap the
+   * resource will be disposed by calling its Dispose method. The caller of
+   * this function should not otherwise delete or modify the resource. Neither
+   * should the underlying buffer be deallocated or modified except through the
+   * destructor of the external string resource.
    */
   static Local<String> NewExternal(ExternalStringResource* resource);
 
@@ -1136,17 +1167,18 @@
    * will use the external string resource. The external string resource's
    * character contents needs to be equivalent to this string.
    * Returns true if the string has been changed to be an external string.
-   * The string is not modified if the operation fails.
+   * The string is not modified if the operation fails. See NewExternal for
+   * information on the lifetime of the resource.
    */
   bool MakeExternal(ExternalStringResource* resource);
 
   /**
    * Creates a new external string using the ascii data defined in the given
-   * resource. The resource is deleted when the external string is no
-   * longer live on V8's heap. The caller of this function should not
-   * delete or modify the resource. Neither should the underlying buffer be
-   * deallocated or modified except through the destructor of the
-   * external string resource.
+   * resource. When the external string is no longer live on V8's heap the
+   * resource will be disposed by calling its Dispose method. The caller of
+   * this function should not otherwise delete or modify the resource. Neither
+   * should the underlying buffer be deallocated or modified except through the
+   * destructor of the external string resource.
    */
   static Local<String> NewExternal(ExternalAsciiStringResource* resource);
 
@@ -1156,7 +1188,8 @@
    * will use the external string resource. The external string resource's
    * character contents needs to be equivalent to this string.
    * Returns true if the string has been changed to be an external string.
-   * The string is not modified if the operation fails.
+   * The string is not modified if the operation fails. See NewExternal for
+   * information on the lifetime of the resource.
    */
   bool MakeExternal(ExternalAsciiStringResource* resource);
 
@@ -1726,13 +1759,22 @@
                                              Local<Value> value,
                                              const AccessorInfo& info);
 
-
 /**
  * Returns a non-empty handle if the interceptor intercepts the request.
- * The result is true if the property exists and false otherwise.
+ * The result is either boolean (true if property exists and false
+ * otherwise) or an integer encoding property attributes.
  */
+#ifdef USE_NEW_QUERY_CALLBACKS
+typedef Handle<Integer> (*NamedPropertyQuery)(Local<String> property,
+                                              const AccessorInfo& info);
+#else
 typedef Handle<Boolean> (*NamedPropertyQuery)(Local<String> property,
                                               const AccessorInfo& info);
+#endif
+
+typedef Handle<Value> (*NamedPropertyQueryImpl)(Local<String> property,
+                                                const AccessorInfo& info);
+
 
 
 /**
@@ -1984,7 +2026,16 @@
                                        NamedPropertyQuery query,
                                        NamedPropertyDeleter remover,
                                        NamedPropertyEnumerator enumerator,
-                                       Handle<Value> data);
+                                       Handle<Value> data) {
+    NamedPropertyQueryImpl casted =
+        reinterpret_cast<NamedPropertyQueryImpl>(query);
+    SetNamedInstancePropertyHandlerImpl(getter,
+                                        setter,
+                                        casted,
+                                        remover,
+                                        enumerator,
+                                        data);
+  }
   void SetIndexedInstancePropertyHandler(IndexedPropertyGetter getter,
                                          IndexedPropertySetter setter,
                                          IndexedPropertyQuery query,
@@ -1996,6 +2047,13 @@
 
   friend class Context;
   friend class ObjectTemplate;
+ private:
+  void SetNamedInstancePropertyHandlerImpl(NamedPropertyGetter getter,
+                                           NamedPropertySetter setter,
+                                           NamedPropertyQueryImpl query,
+                                           NamedPropertyDeleter remover,
+                                           NamedPropertyEnumerator enumerator,
+                                           Handle<Value> data);
 };
 
 
@@ -2053,7 +2111,7 @@
    *
    * \param getter The callback to invoke when getting a property.
    * \param setter The callback to invoke when setting a property.
-   * \param query The callback to invoke to check is an object has a property.
+   * \param query The callback to invoke to check if an object has a property.
    * \param deleter The callback to invoke when deleting a property.
    * \param enumerator The callback to invoke to enumerate all the named
    *   properties of an object.
@@ -2065,7 +2123,26 @@
                                NamedPropertyQuery query = 0,
                                NamedPropertyDeleter deleter = 0,
                                NamedPropertyEnumerator enumerator = 0,
-                               Handle<Value> data = Handle<Value>());
+                               Handle<Value> data = Handle<Value>()) {
+    NamedPropertyQueryImpl casted =
+        reinterpret_cast<NamedPropertyQueryImpl>(query);
+    SetNamedPropertyHandlerImpl(getter,
+                                setter,
+                                casted,
+                                deleter,
+                                enumerator,
+                                data);
+  }
+
+ private:
+  void SetNamedPropertyHandlerImpl(NamedPropertyGetter getter,
+                                   NamedPropertySetter setter,
+                                   NamedPropertyQueryImpl query,
+                                   NamedPropertyDeleter deleter,
+                                   NamedPropertyEnumerator enumerator,
+                                   Handle<Value> data);
+
+ public:
 
   /**
    * Sets an indexed property handler on the object template.
@@ -2335,15 +2412,6 @@
 typedef void (*GCCallback)();
 
 
-// --- C o n t e x t  G e n e r a t o r ---
-
-/**
- * Applications must provide a callback function which is called to generate
- * a context if a context was not deserialized from the snapshot.
- */
-typedef Persistent<Context> (*ContextGenerator)();
-
-
 /**
  * Profiler modules.
  *
@@ -3177,7 +3245,7 @@
   static const int kProxyProxyOffset = sizeof(void*);
   static const int kJSObjectHeaderSize = 3 * sizeof(void*);
   static const int kFullStringRepresentationMask = 0x07;
-  static const int kExternalTwoByteRepresentationTag = 0x03;
+  static const int kExternalTwoByteRepresentationTag = 0x02;
 
   // These constants are compiler dependent so their values must be
   // defined within the implementation.