Fix failures after removing FX_BSTRC.

TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1528743002 .
diff --git a/core/src/fxcrt/fx_basic_wstring.cpp b/core/src/fxcrt/fx_basic_wstring.cpp
index 2e92370..78746e3 100644
--- a/core/src/fxcrt/fx_basic_wstring.cpp
+++ b/core/src/fxcrt/fx_basic_wstring.cpp
@@ -288,7 +288,7 @@
 }
 CFX_ByteString CFX_WideString::UTF16LE_Encode() const {
   if (m_pData == NULL) {
-    return CFX_ByteString("\0\0");
+    return CFX_ByteString("\0\0", 2);
   }
   int len = m_pData->m_nDataLength;
   CFX_ByteString result;
diff --git a/core/src/fxcrt/fx_basic_wstring_unittest.cpp b/core/src/fxcrt/fx_basic_wstring_unittest.cpp
index ad9bcf6..64d694c 100644
--- a/core/src/fxcrt/fx_basic_wstring_unittest.cpp
+++ b/core/src/fxcrt/fx_basic_wstring_unittest.cpp
@@ -281,12 +281,12 @@
     CFX_WideString ws;
     CFX_ByteString bs;
   } utf16le_encode_cases[] = {
-      {L"", CFX_ByteString("\0\0")},
-      {L"abc", CFX_ByteString("a\0b\0c\0\0\0")},
-      {L"abcdef", CFX_ByteString("a\0b\0c\0d\0e\0f\0\0\0")},
-      {L"abc\0def", CFX_ByteString("a\0b\0c\0\0\0")},
-      {L"\xaabb\xccdd", CFX_ByteString("\xbb\xaa\xdd\xcc\0\0")},
-      {L"\x3132\x6162", CFX_ByteString("\x32\x31\x62\x61\0\0")},
+      {L"", CFX_ByteString("\0\0", 2)},
+      {L"abc", CFX_ByteString("a\0b\0c\0\0\0", 8)},
+      {L"abcdef", CFX_ByteString("a\0b\0c\0d\0e\0f\0\0\0", 14)},
+      {L"abc\0def", CFX_ByteString("a\0b\0c\0\0\0", 8)},
+      {L"\xaabb\xccdd", CFX_ByteString("\xbb\xaa\xdd\xcc\0\0", 6)},
+      {L"\x3132\x6162", CFX_ByteString("\x32\x31\x62\x61\0\0", 6)},
   };
 
   for (size_t i = 0; i < FX_ArraySize(utf16le_encode_cases); ++i) {