Add StringBuilder::erase(index)

third_party/WebKit/Source/platform/wtf/text/StringBuilderTest.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 192 matching lines @@
   ExpectBuilderContent("01234567", builder);
 
   builder.ToString();
   builder.Resize(7);
   EXPECT_EQ(7U, builder.length());
   ExpectBuilderContent("0123456", builder);
   builder.Resize(0);
   ExpectEmpty(builder);
 }
 
+TEST(StringBuilderTest, Erase) {
+  StringBuilder builder;
+  builder.Append(String("01234"));
+  // Erase from String.
+  builder.erase(3);
+  ExpectBuilderContent("0124", builder);
+  // Erase from buffer.
+  builder.erase(1);
+  ExpectBuilderContent("024", builder);
+}
+
+TEST(StringBuilderTest, Erase16) {
+  StringBuilder builder;
+  builder.Append(String(u"\uFF10\uFF11\uFF12\uFF13\uFF14"));
+  // Erase from String.
+  builder.erase(3);
+  ExpectBuilderContent(u"\uFF10\uFF11\uFF12\uFF14", builder);
+  // Erase from buffer.
+  builder.erase(1);
+  ExpectBuilderContent(u"\uFF10\uFF12\uFF14", builder);
+}
+
+TEST(StringBuilderTest, EraseLast) {
+  StringBuilder builder;
+  builder.Append("01234");
+  builder.erase(4);
+  ExpectBuilderContent("0123", builder);
+}
+
 TEST(StringBuilderTest, Equal) {
   StringBuilder builder1;
   StringBuilder builder2;
   EXPECT_TRUE(builder1 == builder2);
   EXPECT_TRUE(Equal(builder1, static_cast<LChar*>(0), 0));
   EXPECT_TRUE(builder1 == String());
   EXPECT_TRUE(String() == builder1);
   EXPECT_TRUE(builder1 != String("abc"));
 
   builder1.Append("123");
@@ skipping 109 matching lines @@
   StringBuilder reference;
   reference.Append(kReplacementCharacter);  // Make it UTF-16.
   reference.Append(String::Number(kSomeNumber));
   StringBuilder test;
   test.Append(kReplacementCharacter);
   test.AppendNumber(kSomeNumber);
   EXPECT_EQ(reference, test);
 }
 
 }  // namespace WTF