Reland Use CopyOnWriteBuffer instead of Buffer to avoid unnecessary copies.

webrtc/base/buffer_unittest.cc

Index: webrtc/base/buffer_unittest.cc
diff --git a/webrtc/base/buffer_unittest.cc b/webrtc/base/buffer_unittest.cc
index 7c654477f3be47d16d36a09b387e5a683acb1def..2f3bcfd6060ad8afe5c4ed8563badddd82ca3ee4 100644
--- a/webrtc/base/buffer_unittest.cc
+++ b/webrtc/base/buffer_unittest.cc
@@ -64,23 +64,6 @@ TEST(BufferTest, TestConstructArray) {
   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);