Add missing operators for CFX_WideString

core/src/fxcrt/fx_basic_wstring_unittest.cpp

-// Copyright 2014 PDFium Authors. All rights reserved.
+// Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "../../../testing/fx_string_testhelpers.h"
 #include "../../include/fxcrt/fx_basic.h"
 
+TEST(fxcrt, WideStringOperatorSubscript) {
+    // CFX_WideString includes the NUL terminator for non-empty strings.
+    CFX_WideString abc(L"abc");
+    EXPECT_EQ(L'a', abc[0]);
+    EXPECT_EQ(L'b', abc[1]);
+    EXPECT_EQ(L'c', abc[2]);
+    EXPECT_EQ(L'\0', abc[3]);
+}
+
+TEST(fxcrt, WideStringOperatorLT) {
+    CFX_WideString empty;
+    CFX_WideString a(L"a");
+    CFX_WideString abc(L"\x0110qq");  // Comes before despite endianness.
+    CFX_WideString def(L"\x1001qq");  // Comes after despite endianness.
+
+    EXPECT_FALSE(empty < empty);
+    EXPECT_FALSE(a < a);
+    EXPECT_FALSE(abc < abc);
+    EXPECT_FALSE(def < def);
+
+    EXPECT_TRUE(empty < a);
+    EXPECT_FALSE(a < empty);
+
+    EXPECT_TRUE(empty < abc);
+    EXPECT_FALSE(abc < empty);
+
+    EXPECT_TRUE(empty < def);
+    EXPECT_FALSE(def < empty);
+
+    EXPECT_TRUE(a < abc);
+    EXPECT_FALSE(abc < a);
+
+    EXPECT_TRUE(a < def);
+    EXPECT_FALSE(def < a);
+
+    EXPECT_TRUE(abc < def);
+    EXPECT_FALSE(def < abc);
+}
+
 #define ByteStringLiteral(str) CFX_ByteString(FX_BSTRC(str))
 
 TEST(fxcrt, WideStringUTF16LE_Encode) {
   struct UTF16LEEncodeCase {
     CFX_WideString ws;
     CFX_ByteString bs;
   } utf16le_encode_cases[] = {
     { L"", ByteStringLiteral("\0\0") },
     { L"abc", ByteStringLiteral("a\0b\0c\0\0\0") },
     { L"abcdef", ByteStringLiteral("a\0b\0c\0d\0e\0f\0\0\0") },
     { L"abc\0def", ByteStringLiteral("a\0b\0c\0\0\0") },
     { L"\xaabb\xccdd", ByteStringLiteral("\xbb\xaa\xdd\xcc\0\0") },
     { L"\x3132\x6162", ByteStringLiteral("\x32\x31\x62\x61\0\0") },
   };
 
   for (size_t i = 0; i < FX_ArraySize(utf16le_encode_cases); ++i) {
     EXPECT_EQ(utf16le_encode_cases[i].bs,
         utf16le_encode_cases[i].ws.UTF16LE_Encode())
         << " for case number " << i;
   }
 }