Make tcp_client_socket_unittest pass on Linux....

base/message_loop.h

Index: base/message_loop.h
===================================================================
--- base/message_loop.h	(revision 2267)
+++ base/message_loop.h	(working copy)
@@ -21,6 +21,8 @@
 // We need this to declare base::MessagePumpWin::Dispatcher, which we should
 // really just eliminate.
 #include "base/message_pump_win.h"
+#elif defined(OS_POSIX)
+#include "base/message_pump_libevent.h"
 #endif
 
 // A MessageLoop is used to process events for a particular thread.  There is
@@ -274,6 +276,11 @@
   base::MessagePumpWin* pump_win() {
     return static_cast<base::MessagePumpWin*>(pump_.get());
   }
+#elif defined(OS_POSIX)
+  base::MessagePumpLibevent* pump_libevent() {
+    return static_cast<base::MessagePumpLibevent*>(pump_.get());
+  }
+ protected:
 #endif
 
   // A function to encapsulate all the exception handling capability in the
@@ -450,6 +457,14 @@
 
   // Please see MessagePumpWin for definitions of these methods.
   void WatchObject(HANDLE object, Watcher* watcher);
+
+#elif defined(OS_POSIX)
+  typedef base::MessagePumpLibevent::Watcher Watcher;
+
+  // Please see MessagePumpLibevent for definitions of these methods.
+  void WatchSocket(int socket, short interest_mask, 
+                   struct event* e, Watcher* watcher);
+  void UnwatchSocket(struct event* e);
 #endif  // defined(OS_WIN)
 };