Make socket send and receive more robust and return 0 on failure.

src/platform-win32.cc

Index: src/platform-win32.cc
diff --git a/src/platform-win32.cc b/src/platform-win32.cc
index 9e377a1977700840306f9f631e51d740091ff79b..aa2a71af54f8a29b97d0084afb19e901a03a0639 100644
--- a/src/platform-win32.cc
+++ b/src/platform-win32.cc
@@ -1848,14 +1848,16 @@ bool Win32Socket::Shutdown() {
 
 
 int Win32Socket::Send(const char* data, int len) const {
+  if (len <= 0) return 0;
   int status = send(socket_, data, len, 0);
-  return status;
+  return (status == SOCKET_ERROR) ? 0 : status;
 }
 
 
 int Win32Socket::Receive(char* data, int len) const {
+  if (len <= 0) return 0;
   int status = recv(socket_, data, len, 0);
-  return status;
+  return (status == SOCKET_ERROR) ? 0 : status;
 }