Print Preview: change getPreview to cr.sendWithPromise

chrome/browser/ui/webui/print_preview/print_preview_handler.h

Index: chrome/browser/ui/webui/print_preview/print_preview_handler.h
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_handler.h b/chrome/browser/ui/webui/print_preview/print_preview_handler.h
index 3fc478f6df48099b254b681173b765a7a2be6c43..954d68bea61009349110f572d73199414fcaa98f 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.h
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.h
@@ -7,6 +7,7 @@
 
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
@@ -74,7 +75,13 @@ class PrintPreviewHandler
       const GoogleServiceAuthError& error) override;
 
   // Called when print preview failed.
-  void OnPrintPreviewFailed();
+  void OnPrintPreviewFailed(int request_id);
+
+  // Called when printer settings were invalid.
+  void OnInvalidPrinterSettings(int request_id);
+
+  // Called when print preview is ready.
+  void OnPrintPreviewReady(int preview_uid, int request_id);
 
 #if BUILDFLAG(ENABLE_BASIC_PRINTING)
   // Called when the user press ctrl+shift+p to display the native system
@@ -421,6 +428,8 @@ class PrintPreviewHandler
   // notify the test if it was a successful save, only that it was attempted.
   base::Closure pdf_file_saved_closure_;
 
+  std::vector<std::string> preview_callbacks_;
+
 #if BUILDFLAG(ENABLE_SERVICE_DISCOVERY)
   // Callback ID to be used to notify UI that privet search is finished.
   std::string privet_search_callback_id_;