Improve error handling in the process library.

runtime/bin/socket_linux.cc

Index: runtime/bin/socket_linux.cc
diff --git a/runtime/bin/socket_linux.cc b/runtime/bin/socket_linux.cc
index c50117acd75d3b927bf40be79ecd96831e88887b..73b2c44dee9d17f9741d4a6bc71b03d25aacf901 100644
--- a/runtime/bin/socket_linux.cc
+++ b/runtime/bin/socket_linux.cc
@@ -63,20 +63,20 @@ intptr_t Socket::Available(intptr_t fd) {
 intptr_t Socket::Read(intptr_t fd,
                       void* buffer,
                       intptr_t num_bytes) {
-  assert(fd >= 0);
+  ASSERT(fd >= 0);
   intptr_t read_bytes = read(fd, buffer, num_bytes);
   return read_bytes;
 }
 
 
 intptr_t Socket::Write(intptr_t fd, const void* buffer, intptr_t num_bytes) {
-  assert(fd >= 0);
+  ASSERT(fd >= 0);
   return write(fd, buffer, num_bytes);
 }
 
 
 intptr_t Socket::GetPort(intptr_t fd) {
-  assert(fd >= 0);
+  ASSERT(fd >= 0);
   struct sockaddr_in socket_address;
   socklen_t size = sizeof(socket_address);
   if (getsockname(fd, reinterpret_cast<struct sockaddr *>(&socket_address),