Remove PrintBackend::GetPrinterCapsAndDefaults() from most platforms

GetPrinterCapsAndDefaults() has no callers. Save the implementation in
PrintBackendWin because that one looks useful.

The PrintBackendCUPS version does have an internal caller. Simplify this
version and rename it to GetPrinterCapabilities().

Change-Id: I5475cfe01d1c5994e3937a250d4349b11c356c4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4368803
Reviewed-by: Alan Screen <awscreen@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1122029}

printing/backend/print_backend.h

@@ -277,10 +277,13 @@ class COMPONENT_EXPORT(PRINT_BACKEND) PrintBackend
       const std::string& printer_name,
       PrinterSemanticCapsAndDefaults* printer_info) = 0;
 
+#if BUILDFLAG(IS_WIN)
   // Gets the capabilities and defaults for a specific printer.
+  // TODO(crbug.com/1008222): Evaluate if this code is useful and delete if not.
   virtual mojom::ResultCode GetPrinterCapsAndDefaults(
       const std::string& printer_name,
       PrinterCapsAndDefaults* printer_info) = 0;
+#endif
 
   // Gets the information about driver for a specific printer.
   virtual std::string GetPrinterDriverInfo(const std::string& printer_name) = 0;

printing/backend/print_backend_chromeos.cc

@@ -30,9 +30,6 @@ class PrintBackendChromeOS : public PrintBackend {
   mojom::ResultCode GetPrinterBasicInfo(
       const std::string& printer_name,
       PrinterBasicInfo* printer_info) override;
-  mojom::ResultCode GetPrinterCapsAndDefaults(
-      const std::string& printer_name,
-      PrinterCapsAndDefaults* printer_info) override;
   mojom::ResultCode GetPrinterSemanticCapsAndDefaults(
       const std::string& printer_name,
       PrinterSemanticCapsAndDefaults* printer_info) override;
@@ -54,13 +51,6 @@ mojom::ResultCode PrintBackendChromeOS::GetPrinterBasicInfo(
   return mojom::ResultCode::kFailed;
 }
 
-mojom::ResultCode PrintBackendChromeOS::GetPrinterCapsAndDefaults(
-    const std::string& printer_name,
-    PrinterCapsAndDefaults* printer_info) {
-  NOTREACHED();
-  return mojom::ResultCode::kFailed;
-}
-
 mojom::ResultCode PrintBackendChromeOS::GetPrinterSemanticCapsAndDefaults(
     const std::string& printer_name,
     PrinterSemanticCapsAndDefaults* printer_info) {

printing/backend/print_backend_cups.cc

@@ -240,51 +240,39 @@ mojom::ResultCode PrintBackendCUPS::GetPrinterBasicInfo(
 mojom::ResultCode PrintBackendCUPS::GetPrinterSemanticCapsAndDefaults(
     const std::string& printer_name,
     PrinterSemanticCapsAndDefaults* printer_info) {
-  PrinterCapsAndDefaults info;
   if (!IsValidPrinter(printer_name))
     return mojom::ResultCode::kFailed;
 
-  mojom::ResultCode result_code =
-      GetPrinterCapsAndDefaults(printer_name, &info);
-  if (result_code != mojom::ResultCode::kSuccess)
-    return result_code;
+  std::string printer_capabilities = GetPrinterCapabilities(printer_name);
+  if (printer_capabilities.empty()) {
+    return mojom::ResultCode::kFailed;
+  }
 
   ScopedDestination dest = GetNamedDest(printer_name);
-  return ParsePpdCapabilities(dest.get(), locale_, info.printer_capabilities,
+  return ParsePpdCapabilities(dest.get(), locale_, printer_capabilities,
                               printer_info)
              ? mojom::ResultCode::kSuccess
              : mojom::ResultCode::kFailed;
 }
 
-mojom::ResultCode PrintBackendCUPS::GetPrinterCapsAndDefaults(
-    const std::string& printer_name,
-    PrinterCapsAndDefaults* printer_info) {
-  DCHECK(printer_info);
-
+std::string PrintBackendCUPS::GetPrinterCapabilities(
+    const std::string& printer_name) {
   VLOG(1) << "CUPS: Getting caps and defaults, printer name: " << printer_name;
 
   base::FilePath ppd_path(GetPPD(printer_name.c_str()));
   // In some cases CUPS failed to get ppd file.
   if (ppd_path.empty()) {
     LOG(ERROR) << "CUPS: Failed to get PPD, printer name: " << printer_name;
-    return mojom::ResultCode::kFailed;
+    return std::string();
   }
 
   std::string content;
-  bool res = base::ReadFileToString(ppd_path, &content);
+  if (!base::ReadFileToString(ppd_path, &content)) {
+    content.clear();
+  }
 
   base::DeleteFile(ppd_path);
-
-  if (!res)
-    return mojom::ResultCode::kFailed;
-
-  printer_info->printer_capabilities.swap(content);
-  printer_info->caps_mime_type = "application/pagemaker";
-  // In CUPS, printer defaults is a part of PPD file. Nothing to upload here.
-  printer_info->printer_defaults.clear();
-  printer_info->defaults_mime_type.clear();
-
-  return mojom::ResultCode::kSuccess;
+  return content;
 }
 
 std::string PrintBackendCUPS::GetPrinterDriverInfo(

printing/backend/print_backend_cups.h

@@ -51,12 +51,11 @@ class PrintBackendCUPS : public PrintBackend {
   mojom::ResultCode GetPrinterSemanticCapsAndDefaults(
       const std::string& printer_name,
       PrinterSemanticCapsAndDefaults* printer_info) override;
-  mojom::ResultCode GetPrinterCapsAndDefaults(
-      const std::string& printer_name,
-      PrinterCapsAndDefaults* printer_info) override;
   std::string GetPrinterDriverInfo(const std::string& printer_name) override;
   bool IsValidPrinter(const std::string& printer_name) override;
 
+  std::string GetPrinterCapabilities(const std::string& printer_name);
+
   // The following functions are wrappers around corresponding CUPS functions.
   // <functions>2() are called when print server is specified, and plain version
   // in another case. There is an issue specifying CUPS_HTTP_DEFAULT in the

printing/backend/print_backend_cups_ipp.cc

@@ -87,13 +87,6 @@ mojom::ResultCode PrintBackendCupsIpp::GetPrinterBasicInfo(
                                               : mojom::ResultCode::kFailed;
 }
 
-mojom::ResultCode PrintBackendCupsIpp::GetPrinterCapsAndDefaults(
-    const std::string& printer_name,
-    PrinterCapsAndDefaults* printer_info) {
-  NOTREACHED();
-  return mojom::ResultCode::kFailed;
-}
-
 mojom::ResultCode PrintBackendCupsIpp::GetPrinterSemanticCapsAndDefaults(
     const std::string& printer_name,
     PrinterSemanticCapsAndDefaults* printer_info) {

printing/backend/print_backend_cups_ipp.h

@@ -28,9 +28,6 @@ class PrintBackendCupsIpp : public PrintBackend {
   mojom::ResultCode GetPrinterBasicInfo(
       const std::string& printer_name,
       PrinterBasicInfo* printer_info) override;
-  mojom::ResultCode GetPrinterCapsAndDefaults(
-      const std::string& printer_name,
-      PrinterCapsAndDefaults* printer_info) override;
   mojom::ResultCode GetPrinterSemanticCapsAndDefaults(
       const std::string& printer_name,
       PrinterSemanticCapsAndDefaults* printer_info) override;

printing/backend/print_backend_dummy.cc

@@ -41,12 +41,6 @@ class DummyPrintBackend : public PrintBackend {
     return mojom::ResultCode::kFailed;
   }
 
-  mojom::ResultCode GetPrinterCapsAndDefaults(
-      const std::string& printer_name,
-      PrinterCapsAndDefaults* printer_info) override {
-    return mojom::ResultCode::kFailed;
-  }
-
   std::string GetPrinterDriverInfo(const std::string& printer_name) override {
     return std::string();
   }

printing/backend/test_print_backend.cc

@@ -51,10 +51,12 @@ mojom::ResultCode ReportErrorNoDevice(const base::Location& from_here) {
   return mojom::ResultCode::kFailed;
 }
 
+#if BUILDFLAG(IS_WIN)
 mojom::ResultCode ReportErrorNotImplemented(const base::Location& from_here) {
   DLOG(ERROR) << from_here.ToString() << " failed, method not implemented";
   return mojom::ResultCode::kFailed;
 }
+#endif  // BUILDFLAG(IS_WIN)
 
 }  // namespace
 
@@ -124,11 +126,13 @@ mojom::ResultCode TestPrintBackend::GetPrinterSemanticCapsAndDefaults(
   return mojom::ResultCode::kSuccess;
 }
 
+#if BUILDFLAG(IS_WIN)
 mojom::ResultCode TestPrintBackend::GetPrinterCapsAndDefaults(
     const std::string& printer_name,
     PrinterCapsAndDefaults* printer_caps) {
   return ReportErrorNotImplemented(FROM_HERE);
 }
+#endif  // BUILDFLAG(IS_WIN)
 
 std::string TestPrintBackend::GetPrinterDriverInfo(
     const std::string& printer_name) {

printing/backend/test_print_backend.h

@@ -35,9 +35,11 @@ class TestPrintBackend : public PrintBackend {
   mojom::ResultCode GetPrinterSemanticCapsAndDefaults(
       const std::string& printer_name,
       PrinterSemanticCapsAndDefaults* printer_info) override;
+#if BUILDFLAG(IS_WIN)
   mojom::ResultCode GetPrinterCapsAndDefaults(
       const std::string& printer_name,
       PrinterCapsAndDefaults* printer_info) override;
+#endif
   std::string GetPrinterDriverInfo(const std::string& printer_name) override;
   bool IsValidPrinter(const std::string& printer_name) override;
 #if BUILDFLAG(IS_WIN)