PPAPI/NaCl: Make nacl_ipc_adapter handle ImageData creation

ppapi/proxy/serialized_structs.h

Index: ppapi/proxy/serialized_structs.h
diff --git a/ppapi/proxy/serialized_structs.h b/ppapi/proxy/serialized_structs.h
index f1d90f21a2b936837a4217b6fc25c03b18da50de..b60e765bed8d76bbbe6a9ff46c6451dbedb780bc 100644
--- a/ppapi/proxy/serialized_structs.h
+++ b/ppapi/proxy/serialized_structs.h
@@ -109,6 +109,22 @@ struct PPPVideoCapture_Buffer {
   base::SharedMemoryHandle handle;
 };
 
+// When we share handles to NaCl, we need to know the size. So they should
+// always be provided to the plugin in this struct, so the size is always
+// available.
+struct SerializedSharedMemoryHandle {
+  base::SharedMemoryHandle handle;
+  uint32_t size;
+};
+
+// On Windows, we can't differentiate SharedMemoryHandle from
+// PlatformFileForTransit, since both are just typedefs to HANDLE. We use this
+// type so we can differentiate the two, since when passing the handle to NaCl,
+// we need to know which it is.
+struct SerializedFileDescriptor {
+  IPC::PlatformFileForTransit descriptor;
+};  
+
 #if defined(OS_WIN)
 typedef HANDLE ImageHandle;
 #elif defined(OS_MACOSX) || defined(OS_ANDROID)