Merge to XFA: Change the JS app.viewerType() return value to "pdfium"

fpdfsdk/src/javascript/app.cpp

Index: fpdfsdk/src/javascript/app.cpp
diff --git a/fpdfsdk/src/javascript/app.cpp b/fpdfsdk/src/javascript/app.cpp
index 547446861f8996e2aa2d8d5ed0165c2c2e5d9e53..c8815a0ca171f0066fd375e10b8b823141aac48f 100644
--- a/fpdfsdk/src/javascript/app.cpp
+++ b/fpdfsdk/src/javascript/app.cpp
@@ -188,7 +188,7 @@ FX_BOOL app::viewerType(IFXJS_Context* cc,
                         CJS_PropValue& vp,
                         CFX_WideString& sError) {
   if (vp.IsGetting()) {
-    vp << L"unknown";
+    vp << L"pdfium";
     return TRUE;
   }