PNaCl on-demand installs: Make a separate async IPC to check if PNaCl is installed

ppapi/native_client/src/trusted/plugin/pnacl_coordinator.h

Index: ppapi/native_client/src/trusted/plugin/pnacl_coordinator.h
diff --git a/ppapi/native_client/src/trusted/plugin/pnacl_coordinator.h b/ppapi/native_client/src/trusted/plugin/pnacl_coordinator.h
index 1cd430cfc73c153d2ca92fc756762f3882905b75..06ff7c723460c4935b458451869f16c6a1e3c4c6 100644
--- a/ppapi/native_client/src/trusted/plugin/pnacl_coordinator.h
+++ b/ppapi/native_client/src/trusted/plugin/pnacl_coordinator.h
@@ -148,6 +148,9 @@ class PnaclCoordinator: public CallbackSource<FileStreamData> {
                    const PnaclOptions& pnacl_options,
                    const pp::CompletionCallback& translate_notify_callback);
 
+  // Callback for when we know PNaCl is installed.
+  void DidCheckPnaclInstalled(int32_t pp_error);
+
   // Callback for when the resource info JSON file has been read.
   void ResourceInfoWasRead(int32_t pp_error);