Merge to XFA: Fix JS seconds since epoch to date conversions.

BUG=515137,564736
TBR=ochang@chromium.org, tsepez@chromium.org

Review URL: https://codereview.chromium.org/1533233002 .
Review URL: https://codereview.chromium.org/1544493003 .

(cherry picked from commit b426e3edde040089b70d1a223c83b90957aa571d)
(cherry picked from commit bd35d484a4027775f19ff93e9143e0b270133d42)

Review URL: https://codereview.chromium.org/1546443002 .
diff --git a/BUILD.gn b/BUILD.gn
index 81d874b..8047660 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1517,7 +1517,12 @@
   ]
   include_dirs = []
   if (pdf_enable_v8) {
-    sources += [ "fpdfsdk/src/jsapi/fxjs_v8_embeddertest.cpp" ]
+    sources += [
+      "fpdfsdk/src/javascript/public_methods_embeddertest.cpp",
+      "fpdfsdk/src/jsapi/fxjs_v8_embeddertest.cpp",
+      "testing/js_embedder_test.cpp",
+      "testing/js_embedder_test.h",
+    ]
     deps += [
       "//v8",
       "//v8:v8_libplatform",