Fix compilation after r23865.

TBR=ulan@chromium.org
BUG=

Review URL: https://codereview.chromium.org/549043003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23867 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -130,7 +130,7 @@ class Heap;
 class HeapObject;
 class Isolate;
 class Object;
-class StreamedSource;
+struct StreamedSource;
 template<typename T> class CustomArguments;
 class PropertyCallbackArguments;
 class FunctionCallbackArguments;