Merge to XFA: Make JS app.setTimeOut() work again.

This regressed in commit 794c9b6.

BUG=551248
TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1424743006 .

(cherry picked from commit 8cadf995e9a0fec8da19f69edac9d10fccca7eed)
(cherry picked from commit 955930dce7e4b5c764cdd34b134baea4207de523)

Review URL: https://codereview.chromium.org/1416663008 .
diff --git a/testing/test_support.cpp b/testing/test_support.cpp
index 611ba5d..4923299 100644
--- a/testing/test_support.cpp
+++ b/testing/test_support.cpp
@@ -98,6 +98,22 @@
   return buffer;
 }
 
+std::wstring GetWideString(FPDF_WIDESTRING wstr) {
+  if (!wstr)
+    return nullptr;
+
+  size_t characters = 0;
+  while (wstr[characters])
+    ++characters;
+
+  std::wstring platform_string(characters, L'\0');
+  for (size_t i = 0; i < characters + 1; ++i) {
+    const unsigned char* ptr = reinterpret_cast<const unsigned char*>(&wstr[i]);
+    platform_string[i] = ptr[0] + 256 * ptr[1];
+  }
+  return platform_string;
+}
+
 #ifdef PDF_ENABLE_V8
 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
 bool InitializeV8ForPDFium(const std::string& exe_path,