Fix clang style warnings in webrtc/base

Mostly this consists of marking functions with override when
applicable, and moving function bodies from .h to .cc files.

Not inlining virtual functions with simple bodies such as

  { return false; }

strikes me as probably losing more in readability than we gain in
binary size and compilation time, but I guess it's just like any other
case where enabling a generally good warning forces us to write
slightly worse code in a couple of places.

BUG=163
R=kjellander@webrtc.org, tommi@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/47429004

Cr-Commit-Position: refs/heads/master@{#8656}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8656 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/base/socketadapters.cc b/webrtc/base/socketadapters.cc
index 58d40f5..4a2da0a 100644
--- a/webrtc/base/socketadapters.cc
+++ b/webrtc/base/socketadapters.cc
@@ -117,6 +117,13 @@
   ProcessInput(buffer_, &data_len_);
 }
 
+AsyncProxyServerSocket::AsyncProxyServerSocket(AsyncSocket* socket,
+                                               size_t buffer_size)
+    : BufferedReadAdapter(socket, buffer_size) {
+}
+
+AsyncProxyServerSocket::~AsyncProxyServerSocket() = default;
+
 ///////////////////////////////////////////////////////////////////////////////
 
 // This is a SSL v2 CLIENT_HELLO message.
@@ -507,6 +514,8 @@
       user_(username), pass_(password) {
 }
 
+AsyncSocksProxySocket::~AsyncSocksProxySocket() = default;
+
 int AsyncSocksProxySocket::Connect(const SocketAddress& addr) {
   int ret;
   dest_ = addr;