Provide double-byte terminator in Windows font variant name.

When parsing UTF16-LE, the default trailing "\0" from a single-byte
character literal isn't suffucient.

TBR=dsinclair@chromium.org

Bug: 835184
Change-Id: Ie7db53262adbec0ebccb5d0b22752b8c9f5e6229
Reviewed-on: https://pdfium-review.googlesource.com/31191
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
(cherry picked from commit 9f71afb882a9d1294f8a4392b8553e2c285f51c7)
Reviewed-on: https://pdfium-review.googlesource.com/31630
Reviewed-by: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fxge/win32/fx_win32_device.cpp b/core/fxge/win32/fx_win32_device.cpp
index 337f964..4047866 100644
--- a/core/fxge/win32/fx_win32_device.cpp
+++ b/core/fxge/win32/fx_win32_device.cpp
@@ -38,9 +38,9 @@
 
 const struct {
   const char* m_pFaceName;
-  const char* m_pVariantName;
+  const char* m_pVariantName;  // Note: UTF16-LE terminator required.
 } g_VariantNames[] = {
-    {"DFKai-SB", "\x19\x6A\x77\x69\xD4\x9A"},
+    {"DFKai-SB", "\x19\x6A\x77\x69\xD4\x9A\x00\x00"},
 };
 
 const struct {