Stay writable after partial socket writes.

webrtc/base/physicalsocketserver.h

Index: webrtc/base/physicalsocketserver.h
diff --git a/webrtc/base/physicalsocketserver.h b/webrtc/base/physicalsocketserver.h
index ae1f10f596d8b66b49ab5372b1ad4c52186c4321..8409306a4e35c736515e26051162d6fab16b0bc7 100644
--- a/webrtc/base/physicalsocketserver.h
+++ b/webrtc/base/physicalsocketserver.h
@@ -68,8 +68,8 @@ class PhysicalSocketServer : public SocketServer {
   AsyncSocket* CreateAsyncSocket(int type) override;
   AsyncSocket* CreateAsyncSocket(int family, int type) override;
 
-  // Internal Factory for Accept
-  AsyncSocket* WrapSocket(SOCKET s);
+  // Internal Factory for Accept (virtual so it can be overwritten in tests).
+  virtual AsyncSocket* WrapSocket(SOCKET s);
 
   // SocketServer:
   bool Wait(int cms, bool process_io) override;
@@ -161,6 +161,13 @@ class PhysicalSocket : public AsyncSocket, public sigslot::has_slots<> {
   // Make virtual so ::accept can be overwritten in tests.
   virtual SOCKET DoAccept(SOCKET socket, sockaddr* addr, socklen_t* addrlen);
 
+  // Make virtual so ::send can be overwritten in tests.
+  virtual int DoSend(SOCKET socket, const char* buf, int len, int flags);
+
+  // Make virtual so ::sendto can be overwritten in tests.
+  virtual int DoSendTo(SOCKET socket, const char* buf, int len, int flags,
+                       const struct sockaddr* dest_addr, socklen_t addrlen);
+
   void OnResolveResult(AsyncResolverInterface* resolver);
 
   void UpdateLastError();