Inline the fast path for handle creation....

src/handles.h

Index: src/handles.h
===================================================================
--- src/handles.h	(revision 1538)
+++ src/handles.h	(working copy)
@@ -118,7 +118,16 @@
   static int NumberOfHandles();
 
   // Creates a new handle with the given value.
-  static void** CreateHandle(void* value);
+  static inline void** CreateHandle(void* value) {
+    void** result = current_.next;
+    if (result == current_.limit) result = Extend();
+    // Update the current next field, set the value in the created
+    // handle, and return the result.
+    ASSERT(result < current_.limit);
+    current_.next = result + 1;
+    *result = value;
+    return result;
+  }
 
  private:
   // Prevent heap allocation or illegal handle scopes.
@@ -150,6 +159,9 @@
 #endif
   }
 
+  // Extend the handle scope making room for more handles.
+  static void** Extend();
+
   // Deallocates any extensions used by the current scope.
   static void DeleteExtensions();