Printing: Port CupsIppPrintingBackend feature to Linux

Take the existing CupsIppPrintingBackend feature, which is Mac-only, and
enable it on Linux as well. Unlike Mac, where the feature is enabled by
default, it starts out disabled by default on Linux.

Bug: 339188518
Change-Id: Ic06fc593130ee7188ecc9cf54b8f12fbdfc6de46
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5560307
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Reviewed-by: Alan Screen <awscreen@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1304711}

chrome/browser/about_flags.cc

@@ -7037,12 +7037,12 @@ const FeatureEntry kFeatureEntries[] = {
      FEATURE_VALUE_TYPE(printing::features::kAddPrinterViaPrintscanmgr)},
 #endif  // BUILDFLAG(IS_CHROMEOS)
 
-#if BUILDFLAG(IS_MAC)
+#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
     {"cups-ipp-printing-backend",
      flag_descriptions::kCupsIppPrintingBackendName,
-     flag_descriptions::kCupsIppPrintingBackendDescription, kOsMac,
+     flag_descriptions::kCupsIppPrintingBackendDescription, kOsDesktop,
      FEATURE_VALUE_TYPE(printing::features::kCupsIppPrintingBackend)},
-#endif  // BUILDFLAG(IS_MAC)
+#endif  // BUILDFLAG(IS_LINUX) ||BUILDFLAG(IS_MAC)
 
 #if BUILDFLAG(IS_WIN)
     {"print-with-postscript-type42-fonts",

chrome/browser/flag_descriptions.cc

@@ -5462,13 +5462,6 @@ const char kUseXpsForPrintingFromPdfDescription[] =
 
 #if BUILDFLAG(IS_MAC)
 
-#if BUILDFLAG(ENABLE_PRINTING)
-const char kCupsIppPrintingBackendName[] = "CUPS IPP Printing Backend";
-const char kCupsIppPrintingBackendDescription[] =
-    "Use the CUPS IPP printing backend instead of the original CUPS backend "
-    "that calls the PPD API.";
-#endif  // BUILDFLAG(ENABLE_PRINTING)
-
 const char kEnableExtensibleEnterpriseSSOName[] = "Extensible Enterprise SSO";
 const char kEnableExtensibleEnterpriseSSODescription[] =
     "Enables support for extensible enterprise SSO in Chrome";
@@ -7931,6 +7924,13 @@ const char kRestartToGainAccessToKeychainName[] =
 const char kRestartToGainAccessToKeychainDescription[] =
     "Controls whether the Chrome shows bubbles and banner, prompting the user "
     "to restart Chrome to gain access to computer's password manager.";
+
+#if BUILDFLAG(ENABLE_PRINTING)
+const char kCupsIppPrintingBackendName[] = "CUPS IPP Printing Backend";
+const char kCupsIppPrintingBackendDescription[] =
+    "Use the CUPS IPP printing backend instead of the original CUPS backend "
+    "that calls the PPD API.";
+#endif  // BUILDFLAG(ENABLE_PRINTING)
 #endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
 
 #if BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN)

chrome/browser/flag_descriptions.h

@@ -3182,11 +3182,6 @@ extern const char kUseXpsForPrintingFromPdfDescription[];
 
 #if BUILDFLAG(IS_MAC)
 
-#if BUILDFLAG(ENABLE_PRINTING)
-extern const char kCupsIppPrintingBackendName[];
-extern const char kCupsIppPrintingBackendDescription[];
-#endif  // BUILDFLAG(ENABLE_PRINTING)
-
 extern const char kEnableExtensibleEnterpriseSSOName[];
 extern const char kEnableExtensibleEnterpriseSSODescription[];
 
@@ -4599,6 +4594,11 @@ extern const char kForcePasswordInitialSyncWhenDecryptionFailsDescription[];
 
 extern const char kRestartToGainAccessToKeychainName[];
 extern const char kRestartToGainAccessToKeychainDescription[];
+
+#if BUILDFLAG(ENABLE_PRINTING)
+extern const char kCupsIppPrintingBackendName[];
+extern const char kCupsIppPrintingBackendDescription[];
+#endif  // BUILDFLAG(ENABLE_PRINTING)
 #endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
 
 #if BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN)

chrome/common/printing/printer_capabilities.cc

@@ -129,6 +129,8 @@ base::Value AssemblePrinterCapabilities(const std::string& device_name,
 #if BUILDFLAG(PRINT_MEDIA_L10N_ENABLED)
   bool populate_paper_names = true;
 #if BUILDFLAG(IS_MAC)
+  // TODO(crbug.com/339188518): Is this needed on Linux?
+  //
   // Paper display name localization and vendor ID assignment is intended for
   // use with the CUPS IPP backend. If the CUPS IPP backend is not enabled,
   // localization will not properly occur.

printing/backend/print_backend_cups.cc

@@ -26,12 +26,12 @@
 #include "printing/mojom/print.mojom.h"
 #include "url/gurl.h"
 
-#if BUILDFLAG(IS_MAC)
+#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
 #include "base/feature_list.h"
 #include "printing/backend/cups_connection.h"
 #include "printing/backend/print_backend_cups_ipp.h"
 #include "printing/printing_features.h"
-#endif  // BUILDFLAG(IS_MAC)
+#endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
 
 namespace printing {
 
@@ -296,11 +296,11 @@ bool PrintBackendCUPS::IsValidPrinter(const std::string& printer_name) {
 #if !BUILDFLAG(IS_CHROMEOS)
 scoped_refptr<PrintBackend> PrintBackend::CreateInstanceImpl(
     const std::string& locale) {
-#if BUILDFLAG(IS_MAC)
+#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
   if (base::FeatureList::IsEnabled(features::kCupsIppPrintingBackend)) {
     return base::MakeRefCounted<PrintBackendCupsIpp>(CupsConnection::Create());
   }
-#endif  // BUILDFLAG(IS_MAC)
+#endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
   return base::MakeRefCounted<PrintBackendCUPS>(
       GURL(), HTTP_ENCRYPT_NEVER, /*cups_blocking=*/false, locale);
 }

printing/buildflags/buildflags.gni

@@ -63,5 +63,5 @@ declare_args() {
 declare_args() {
   # Enables the CUPS IPP printing backend.
   # TODO(crbug.com/41003486): Remove this after CUPS PPD API calls are removed.
-  use_cups_ipp = use_cups && !is_linux
+  use_cups_ipp = use_cups
 }

printing/printing_features.cc

@@ -21,13 +21,18 @@ BASE_FEATURE(kAddPrinterViaPrintscanmgr,
              base::FEATURE_ENABLED_BY_DEFAULT);
 #endif  // BUILDFLAG(IS_CHROMEOS)
 
-#if BUILDFLAG(IS_MAC)
+#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
 // Use the CUPS IPP printing backend instead of the original CUPS backend that
 // calls the deprecated PPD API.
 BASE_FEATURE(kCupsIppPrintingBackend,
              "CupsIppPrintingBackend",
-             base::FEATURE_ENABLED_BY_DEFAULT);
-#endif  // BUILDFLAG(IS_MAC)
+#if BUILDFLAG(IS_LINUX)
+             base::FEATURE_DISABLED_BY_DEFAULT
+#else
+             base::FEATURE_ENABLED_BY_DEFAULT
+#endif
+);
+#endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
 
 #if BUILDFLAG(IS_WIN)
 // When using PostScript level 3 printing, render text with Type 42 fonts if

printing/printing_features.h

@@ -22,9 +22,9 @@ COMPONENT_EXPORT(PRINTING_BASE)
 BASE_DECLARE_FEATURE(kAddPrinterViaPrintscanmgr);
 #endif  // BUILDFLAG(IS_CHROMEOS)
 
-#if BUILDFLAG(IS_MAC)
+#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
 COMPONENT_EXPORT(PRINTING_BASE) BASE_DECLARE_FEATURE(kCupsIppPrintingBackend);
-#endif  // BUILDFLAG(IS_MAC)
+#endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
 
 #if BUILDFLAG(IS_WIN)
 COMPONENT_EXPORT(PRINTING_BASE)