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}
diff --git a/rtc_base/win32socketserver.h b/rtc_base/win32socketserver.h
index 63b662c..ce29bc5 100644
--- a/rtc_base/win32socketserver.h
+++ b/rtc_base/win32socketserver.h
@@ -30,7 +30,7 @@
 class Win32Socket : public AsyncSocket {
  public:
   Win32Socket();
-  virtual ~Win32Socket();
+  ~Win32Socket() override;
 
   bool CreateT(int family, int type);
 
@@ -38,25 +38,27 @@
   void SetTimeout(int ms);
 
   // AsyncSocket Interface
-  virtual SocketAddress GetLocalAddress() const;
-  virtual SocketAddress GetRemoteAddress() const;
-  virtual int Bind(const SocketAddress& addr);
-  virtual int Connect(const SocketAddress& addr);
-  virtual int Send(const void *buffer, size_t length);
-  virtual int SendTo(const void *buffer, size_t length, const SocketAddress& addr);
-  virtual int Recv(void* buffer, size_t length, int64_t* timestamp);
-  virtual int RecvFrom(void* buffer,
-                       size_t length,
-                       SocketAddress* out_addr,
-                       int64_t* timestamp);
-  virtual int Listen(int backlog);
-  virtual Win32Socket *Accept(SocketAddress *out_addr);
-  virtual int Close();
-  virtual int GetError() const;
-  virtual void SetError(int error);
-  virtual ConnState GetState() const;
-  virtual int GetOption(Option opt, int* value);
-  virtual int SetOption(Option opt, int value);
+  SocketAddress GetLocalAddress() const override;
+  SocketAddress GetRemoteAddress() const override;
+  int Bind(const SocketAddress& addr) override;
+  int Connect(const SocketAddress& addr) override;
+  int Send(const void* buffer, size_t length) override;
+  int SendTo(const void* buffer,
+             size_t length,
+             const SocketAddress& addr) override;
+  int Recv(void* buffer, size_t length, int64_t* timestamp) override;
+  int RecvFrom(void* buffer,
+               size_t length,
+               SocketAddress* out_addr,
+               int64_t* timestamp) override;
+  int Listen(int backlog) override;
+  Win32Socket* Accept(SocketAddress* out_addr) override;
+  int Close() override;
+  int GetError() const override;
+  void SetError(int error) override;
+  ConnState GetState() const override;
+  int GetOption(Option opt, int* value) override;
+  int SetOption(Option opt, int value) override;
 
  private:
   void CreateSink();
@@ -93,22 +95,22 @@
 class Win32SocketServer : public SocketServer {
  public:
   Win32SocketServer();
-  virtual ~Win32SocketServer();
+  ~Win32SocketServer() override;
 
   void set_modeless_dialog(HWND hdlg) {
     hdlg_ = hdlg;
   }
 
   // SocketServer Interface
-  virtual Socket* CreateSocket(int type);
-  virtual Socket* CreateSocket(int family, int type);
+  Socket* CreateSocket(int type) override;
+  Socket* CreateSocket(int family, int type) override;
 
-  virtual AsyncSocket* CreateAsyncSocket(int type);
-  virtual AsyncSocket* CreateAsyncSocket(int family, int type);
+  AsyncSocket* CreateAsyncSocket(int type) override;
+  AsyncSocket* CreateAsyncSocket(int family, int type) override;
 
-  virtual void SetMessageQueue(MessageQueue* queue);
-  virtual bool Wait(int cms, bool process_io);
-  virtual void WakeUp();
+  void SetMessageQueue(MessageQueue* queue) override;
+  bool Wait(int cms, bool process_io) override;
+  void WakeUp() override;
 
   void Pump();
 
@@ -119,7 +121,7 @@
    public:
     explicit MessageWindow(Win32SocketServer* ss) : ss_(ss) {}
    private:
-    virtual bool OnMessage(UINT msg, WPARAM wp, LPARAM lp, LRESULT& result);
+    bool OnMessage(UINT msg, WPARAM wp, LPARAM lp, LRESULT& result) override;
     Win32SocketServer* ss_;
   };
 
@@ -137,18 +139,12 @@
 
 class Win32Thread : public Thread {
  public:
-  explicit Win32Thread(SocketServer* ss) : Thread(ss),  id_(0) {}
-  virtual ~Win32Thread() {
-    Stop();
-  }
-  virtual void Run() {
-    id_ = GetCurrentThreadId();
-    Thread::Run();
-    id_ = 0;
-  }
-  virtual void Quit() {
-    PostThreadMessage(id_, WM_QUIT, 0, 0);
-  }
+  explicit Win32Thread(SocketServer* ss);
+  ~Win32Thread() override;
+
+  void Run() override;
+  void Quit() override;
+
  private:
   DWORD id_;
 };