Move flash clipboard to the new proxy and add custom format support

ppapi/thunk/ppb_instance_api.h

Index: ppapi/thunk/ppb_instance_api.h
diff --git a/ppapi/thunk/ppb_instance_api.h b/ppapi/thunk/ppb_instance_api.h
index f91febd958beb1f74751d2aef7394eb1f7dca587..c5f26e60faa542df11b1a31825010cef56d53509 100644
--- a/ppapi/thunk/ppb_instance_api.h
+++ b/ppapi/thunk/ppb_instance_api.h
@@ -38,6 +38,7 @@ struct ViewData;
 namespace thunk {
 
 class PPB_Flash_API;
+class PPB_Flash_Clipboard_API;
 class PPB_Flash_Functions_API;
 class PPB_Gamepad_API;
 
@@ -95,6 +96,10 @@ class PPB_Instance_API {
   virtual PPB_Flash_Functions_API* GetFlashFunctionsAPI(
       PP_Instance instance) = 0;
 
+  // Flash_Clipboard.
+  virtual PPB_Flash_Clipboard_API* GetFlashClipboardAPI(
+      PP_Instance instance) = 0;
+
   // Gamepad.
   virtual PPB_Gamepad_API* GetGamepadAPI(PP_Instance instance) = 0;