Relanding: Allow the DTLS fingerprint verification to occur after the handshake.

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 bd095a6b0954a5a9dc907ba7aeb4e9db38bc5ae3..df1f5430276e46f6fcff231b495439550173e10b 100644
--- a/webrtc/base/buffer_unittest.cc
+++ b/webrtc/base/buffer_unittest.cc
@@ -357,4 +357,13 @@ TEST(BufferTest, TestStruct) {
   EXPECT_EQ(kObsidian, buf[2].stone);
 }
 
+TEST(BufferTest, TestEmpty) {
+  Buffer buf;
+  EXPECT_TRUE(buf.empty());
+  buf.SetData(kTestData, 15);
+  EXPECT_FALSE(buf.empty());
+  buf.Clear();
+  EXPECT_TRUE(buf.empty());
+}
+
 }  // namespace rtc