Misc fixes for gn builds with VS 2015

printing/printing_context_win_unittest.cc

Index: printing/printing_context_win_unittest.cc
diff --git a/printing/printing_context_win_unittest.cc b/printing/printing_context_win_unittest.cc
index aab83f3e2a1bf035a86d0c8621e507f6a05bdf8f..6b2b20f7bd09b8a6e57985896d492e07ea5f46a6 100644
--- a/printing/printing_context_win_unittest.cc
+++ b/printing/printing_context_win_unittest.cc
@@ -118,13 +118,13 @@ class MockPrintingContextWin : public PrintingContextSytemDialogWin {
     memcpy(reinterpret_cast<uint8*>(dev_names_ptr) + dev_names->wDriverOffset,
            info_2.get()->pDriverName,
            driver_size);
-    dev_names->wDeviceOffset =
-        dev_names->wDriverOffset + driver_size / sizeof(wchar_t);
+    dev_names->wDeviceOffset = base::checked_cast<WORD>(
+        dev_names->wDriverOffset + driver_size / sizeof(wchar_t));
     memcpy(reinterpret_cast<uint8*>(dev_names_ptr) + dev_names->wDeviceOffset,
            info_2.get()->pPrinterName,
            printer_size);
-    dev_names->wOutputOffset =
-        dev_names->wDeviceOffset + printer_size / sizeof(wchar_t);
+    dev_names->wOutputOffset = base::checked_cast<WORD>(
+        dev_names->wDeviceOffset + printer_size / sizeof(wchar_t));
     memcpy(reinterpret_cast<uint8*>(dev_names_ptr) + dev_names->wOutputOffset,
            info_2.get()->pPortName,
            port_size);