Add missing operators for CFX_ByteString.

core/src/fxcrt/fx_basic_bstring_unittest.cpp

Index: core/src/fxcrt/fx_basic_bstring_unittest.cpp
diff --git a/core/src/fxcrt/fx_basic_bstring_unittest.cpp b/core/src/fxcrt/fx_basic_bstring_unittest.cpp
index 53427e36509731c3d523029c1b90697392fb9879..1ddaad420ada97b8581f125dca7eb8a78d0a926d 100644
--- a/core/src/fxcrt/fx_basic_bstring_unittest.cpp
+++ b/core/src/fxcrt/fx_basic_bstring_unittest.cpp
@@ -6,6 +6,45 @@
 #include "../../../testing/fx_string_testhelpers.h"
 #include "../../include/fxcrt/fx_basic.h"
 
+TEST(fxcrt, ByteStringOperatorSubscript) {
+    // CFX_ByteString includes the NUL terminator for non-empty strings.
+    CFX_ByteString abc("abc");
+    EXPECT_EQ('a', abc[0]);
+    EXPECT_EQ('b', abc[1]);
+    EXPECT_EQ('c', abc[2]);
+    EXPECT_EQ(0, abc[3]);
+}
+
+TEST(fxcrt, ByteStringOperatorLT) {
+    CFX_ByteString empty;
+    CFX_ByteString a("a");
+    CFX_ByteString abc("abc");
+    CFX_ByteString def("def");
+
+    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);
+}
+
 TEST(fxcrt, ByteStringCNull) {
   CFX_ByteStringC null_string;
   EXPECT_EQ(null_string.GetPtr(), nullptr);