Move Pickle to base namespace.

ppapi/proxy/serialized_flash_menu.h

Index: ppapi/proxy/serialized_flash_menu.h
diff --git a/ppapi/proxy/serialized_flash_menu.h b/ppapi/proxy/serialized_flash_menu.h
index 271caba368bd4e3d4c988e6731e145e2d29cb68e..8c1d7096067d355022958c881d5b5d5f7741f366 100644
--- a/ppapi/proxy/serialized_flash_menu.h
+++ b/ppapi/proxy/serialized_flash_menu.h
@@ -11,7 +11,9 @@
 #include "base/basictypes.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
 
+namespace base {
 class PickleIterator;
+}
 
 struct PP_Flash_Menu;
 
@@ -32,7 +34,7 @@ class PPAPI_PROXY_EXPORT SerializedFlashMenu {
   const PP_Flash_Menu* pp_menu() const { return pp_menu_; }
 
   void WriteToMessage(IPC::Message* m) const;
-  bool ReadFromMessage(const IPC::Message* m, PickleIterator* iter);
+  bool ReadFromMessage(const IPC::Message* m, base::PickleIterator* iter);
 
  private:
   const PP_Flash_Menu* pp_menu_;