PrintBackendBrowserTest to utilize refactored TestPrintBackend

TestPrintBackend was reworked to include a more consistent behavior
across its interfaces.  With this in place we can now update the testing
for print backend service to use AddValidPrinter() that ensures valid
printer definitions.

This allows the GetDefaultPrinterName test to be re-enabled and prepares
for further updates related to printer capabilities.

Bug: 809738
Change-Id: Iedf2d219da40cb508b6778f70889e86cccfb0052
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2538365Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Commit-Queue: Alan Screen <awscreen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833800}

chrome/browser/printing/print_backend_browsertest.cc

@@ -18,6 +18,7 @@
 #include "content/public/test/browser_test.h"
 #include "mojo/public/cpp/bindings/pending_receiver.h"
 #include "mojo/public/cpp/bindings/pending_remote.h"
+#include "printing/backend/print_backend.h"
 #include "printing/backend/test_print_backend.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -73,8 +74,16 @@ class PrintBackendBrowserTest : public InProcessBrowserTest {
   // Initialize and load the backend service with some test print drivers.
   void DoInitAndSetupTestData() {
     print_backend_service_->Init(/*locale=*/"");
-    print_backend_service_->test_print_backend_->SetDefaultPrinterName(
-        kDefaultPrinterName);
+
+    auto printer_info = std::make_unique<PrinterBasicInfo>(
+        /*printer_name=*/kDefaultPrinterName,
+        /*display_name=*/"default test printer",
+        /*printer_description=*/"Default printer for testing.",
+        /*printer_status=*/0, /*is_default=*/true,
+        /*options=*/PrinterBasicInfoOptions{});
+
+    print_backend_service_->test_print_backend_->AddValidPrinter(
+        kDefaultPrinterName, nullptr, std::move(printer_info));
   }
 
   // Public callbacks used by tests.
@@ -131,10 +140,7 @@ IN_PROC_BROWSER_TEST_F(PrintBackendBrowserTest, FailWithoutInit) {
   EXPECT_FALSE(default_printer_name.has_value());
 }
 
-// TODO(crbug.com/809738):  Re-enable after the updates for setting up the
-// printer test environment are made to print_backend_service.mojom.
-IN_PROC_BROWSER_TEST_F(PrintBackendBrowserTest,
-                       DISABLED_GetDefaultPrinterName) {
+IN_PROC_BROWSER_TEST_F(PrintBackendBrowserTest, GetDefaultPrinterName) {
   base::Optional<std::string> default_printer_name;
 
   DoInitAndSetupTestData();