Reland Use CopyOnWriteBuffer instead of Buffer to avoid unnecessary copies.

webrtc/base/buffer_unittest.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 46 matching lines @@
   EXPECT_EQ(0, memcmp(buf.data(), kTestData, 7));
 }
 
 TEST(BufferTest, TestConstructArray) {
   Buffer buf(kTestData);
   EXPECT_EQ(buf.size(), 16u);
   EXPECT_EQ(buf.capacity(), 16u);
   EXPECT_EQ(0, memcmp(buf.data(), kTestData, 16));
 }
 
-TEST(BufferTest, TestConstructCopy) {
-  Buffer buf1(kTestData), buf2(buf1);
-  EXPECT_EQ(buf2.size(), 16u);
-  EXPECT_EQ(buf2.capacity(), 16u);
-  EXPECT_EQ(0, memcmp(buf2.data(), kTestData, 16));
-  EXPECT_NE(buf1.data(), buf2.data());
-  EXPECT_EQ(buf1, buf2);
-}
-
-TEST(BufferTest, TestAssign) {
-  Buffer buf1, buf2(kTestData, sizeof(kTestData), 256);
-  EXPECT_NE(buf1, buf2);
-  buf1 = buf2;
-  EXPECT_EQ(buf1, buf2);
-  EXPECT_NE(buf1.data(), buf2.data());
-}
-
 TEST(BufferTest, TestSetData) {
   Buffer buf(kTestData + 4, 7);
   buf.SetData(kTestData, 9);
   EXPECT_EQ(buf.size(), 9u);
   EXPECT_EQ(buf.capacity(), 9u);
   EXPECT_EQ(0, memcmp(buf.data(), kTestData, 9));
 }
 
 TEST(BufferTest, TestAppendData) {
   Buffer buf(kTestData + 4, 3);
@@ skipping 218 matching lines @@
   for (size_t i = 0; i != 7u; ++i) {
     buf[i] = kTestData[i];
   }
 
   for (size_t i = 0; i != 7u; ++i) {
     EXPECT_EQ(buf[i], kTestData[i]);
   }
 }
 
 }  // namespace rtc