Add XPS feature helper functions

There are various places in the printing code that need to check if
printing needs to use the GDI or XPS API.  Some printing code is solely
concerned if XPS printing is even a possibility (in particular for
process setup).  Add helper functions to simplify such use cases.

Bug: 1008222
Change-Id: If001018b7bd9615124db21493322fdecbe626573
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2032718
Commit-Queue: Alan Screen <awscreen@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Daniel Hosseinian <dhoss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#745774}

printing/printing_features.cc

@@ -23,6 +23,17 @@ const base::Feature kUseXpsForPrinting{"UseXpsForPrinting",
 // GDI for modifiable content.
 const base::Feature kUseXpsForPrintingFromPdf{
     "UseXpsForPrintingFromPdf", base::FEATURE_DISABLED_BY_DEFAULT};
+
+bool IsXpsPrintCapabilityRequired() {
+  return base::FeatureList::IsEnabled(features::kUseXpsForPrinting) ||
+         base::FeatureList::IsEnabled(features::kUseXpsForPrintingFromPdf);
+}
+
+bool ShouldPrintUsingXps(bool source_is_pdf) {
+  return base::FeatureList::IsEnabled(source_is_pdf
+                                          ? features::kUseXpsForPrintingFromPdf
+                                          : features::kUseXpsForPrinting);
+}
 #endif  // defined(OS_WIN)
 
 }  // namespace features

printing/printing_features.h

@@ -21,6 +21,14 @@ PRINTING_EXPORT extern const base::Feature kAdvancedPpdAttributes;
 #if defined(OS_WIN)
 PRINTING_EXPORT extern const base::Feature kUseXpsForPrinting;
 PRINTING_EXPORT extern const base::Feature kUseXpsForPrintingFromPdf;
+
+// Helper function to determine if there is any print path which could require
+// the use of XPS print capabilities.
+PRINTING_EXPORT bool IsXpsPrintCapabilityRequired();
+
+// Helper function to determine if printing of a document from a particular
+// source should be done using XPS printing API instead of with GDI.
+PRINTING_EXPORT bool ShouldPrintUsingXps(bool source_is_pdf);
 #endif
 
 }  // namespace features