Reland "Enable the clang style plugin in rtc_base/"

This is a reland of Id63f0deb7b335690157ab157c35177b7836688da.

Original change's description:
> Enable the clang style plugin in rtc_base/
> 
> Enabled the plugin and cleaned up all issues it found.
> 
> Bug: webrtc:163
> Change-Id: Id63f0deb7b335690157ab157c35177b7836688da
> Reviewed-on: https://webrtc-review.googlesource.com/14660
> Commit-Queue: Steve Anton <steveanton@webrtc.org>
> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#20401}

Bug: webrtc:163
Change-Id: I861a5fe741215115b0e7a2be9c0786836ff5376e
Reviewed-on: https://webrtc-review.googlesource.com/15040
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20416}

rtc_base/testutils.cc

@@ -0,0 +1,116 @@
+/*
+ *  Copyright 2007 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.
+ */
+
+#include "rtc_base/testutils.h"
+
+namespace webrtc {
+namespace testing {
+
+StreamSink::StreamSink() = default;
+
+StreamSink::~StreamSink() = default;
+
+StreamSource::StreamSource() {
+  Clear();
+}
+
+StreamSource::~StreamSource() = default;
+
+StreamState StreamSource::GetState() const {
+  return state_;
+}
+
+StreamResult StreamSource::Read(void* buffer,
+                                size_t buffer_len,
+                                size_t* read,
+                                int* error) {
+  if (SS_CLOSED == state_) {
+    if (error)
+      *error = -1;
+    return SR_ERROR;
+  }
+  if ((SS_OPENING == state_) || (readable_data_.size() <= read_block_)) {
+    return SR_BLOCK;
+  }
+  size_t count = std::min(buffer_len, readable_data_.size() - read_block_);
+  memcpy(buffer, &readable_data_[0], count);
+  size_t new_size = readable_data_.size() - count;
+  // Avoid undefined access beyond the last element of the vector.
+  // This only happens when new_size is 0.
+  if (count < readable_data_.size()) {
+    memmove(&readable_data_[0], &readable_data_[count], new_size);
+  }
+  readable_data_.resize(new_size);
+  if (read)
+    *read = count;
+  return SR_SUCCESS;
+}
+
+StreamResult StreamSource::Write(const void* data,
+                                 size_t data_len,
+                                 size_t* written,
+                                 int* error) {
+  if (SS_CLOSED == state_) {
+    if (error)
+      *error = -1;
+    return SR_ERROR;
+  }
+  if (SS_OPENING == state_) {
+    return SR_BLOCK;
+  }
+  if (SIZE_UNKNOWN != write_block_) {
+    if (written_data_.size() >= write_block_) {
+      return SR_BLOCK;
+    }
+    if (data_len > (write_block_ - written_data_.size())) {
+      data_len = write_block_ - written_data_.size();
+    }
+  }
+  if (written)
+    *written = data_len;
+  const char* cdata = static_cast<const char*>(data);
+  written_data_.insert(written_data_.end(), cdata, cdata + data_len);
+  return SR_SUCCESS;
+}
+
+void StreamSource::Close() {
+  state_ = SS_CLOSED;
+}
+
+SocketTestClient::SocketTestClient() {
+  Init(nullptr, AF_INET);
+}
+
+SocketTestClient::SocketTestClient(AsyncSocket* socket) {
+  Init(socket, socket->GetLocalAddress().family());
+}
+
+SocketTestClient::SocketTestClient(const SocketAddress& address) {
+  Init(nullptr, address.family());
+  socket_->Connect(address);
+}
+
+SocketTestClient::~SocketTestClient() = default;
+
+SocketTestServer::SocketTestServer(const SocketAddress& address)
+    : socket_(
+          Thread::Current()->socketserver()->CreateAsyncSocket(address.family(),
+                                                               SOCK_STREAM)) {
+  socket_->SignalReadEvent.connect(this, &SocketTestServer::OnReadEvent);
+  socket_->Bind(address);
+  socket_->Listen(5);
+}
+
+SocketTestServer::~SocketTestServer() {
+  clear();
+}
+
+}  // namespace testing
+}  // namespace webrtc