Make CString more similar to WTF::String.

third_party/WebKit/Source/wtf/text/CStringTest.cpp

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 93 matching lines @@
     EXPECT_EQ(0, uninitializedString.data()[length]);
 }
 
 TEST(CStringTest, ZeroTerminated)
 {
     const char* referenceString = "WebKit";
     CString stringWithLength(referenceString, 3);
     EXPECT_EQ(0, stringWithLength.data()[3]);
 }
 
-TEST(CStringTest, CopyOnWrite)
-{
-    const char* initialString = "Webkit";
-    CString string(initialString);
-    CString copy = string;
-
-    string.mutableData()[3] = 'K';
-    EXPECT_TRUE(string != copy);
-    EXPECT_STREQ("WebKit", string.data());
-    EXPECT_STREQ(initialString, copy.data());
-}
-
 TEST(CStringTest, Comparison)
 {
     // Comparison with another CString.
     CString a;
     CString b;
     EXPECT_TRUE(a == b);
     EXPECT_FALSE(a != b);
     a = "a";
     b = CString();
     EXPECT_FALSE(a == b);
@@ skipping 76 matching lines @@
 
 TEST(CStringTest, Printer)
 {
     EXPECT_STREQ("<null>", printedString(CString()).data());
     EXPECT_STREQ("\"abc\"", printedString("abc").data());
     EXPECT_STREQ("\"\\t\\n\\r\\\"\\\\\"", printedString("\t\n\r\"\\").data());
     EXPECT_STREQ("\"\\xFF\\x00\\x01xyz\"", printedString(CString("\xff\0\x01xyz", 6)).data());
 }
 
 } // namespace WTF