Extract XPS code from PrintSystemWin.

BUG=317027

Review URL: https://codereview.chromium.org/61673004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234174 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 25 insertions, 0 deletions

diff --git a/printing/backend/win_helper.h b/printing/backend/win_helper.h
index 9ac9df3..0f6b7ef 100644
--- a/printing/backend/win_helper.h
+++ b/printing/backend/win_helper.h
@@ -62,6 +62,31 @@ class ScopedPrinterHandle
   }
 };
 
+class PrinterChangeHandleTraits {
+ public:
+  typedef HANDLE Handle;
+
+  static bool CloseHandle(HANDLE handle) {
+    ::FindClosePrinterChangeNotification(handle);
+    return true;
+  }
+
+  static bool IsHandleValid(HANDLE handle) {
+    return handle != NULL;
+  }
+
+  static HANDLE NullHandle() {
+    return NULL;
+  }
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(PrinterChangeHandleTraits);
+};
+
+typedef base::win::GenericScopedHandle<PrinterChangeHandleTraits,
+                                       base::win::DummyVerifierTraits>
+    ScopedPrinterChangeHandle;
+
 // Wrapper class to wrap the XPS APIs (PTxxx APIs). This is needed because these
 // APIs are not available by default on XP. We could delayload prntvpt.dll but
 // this would mean having to add that to every binary that links with