Use fake clock in some more networks tests.

webrtc/base/messagequeue.h

Index: webrtc/base/messagequeue.h
diff --git a/webrtc/base/messagequeue.h b/webrtc/base/messagequeue.h
index 628ce4433b824396c952400836d39bd8df023a6c..429a56a8c1e3cd69f6dcafa1b19fbc90dfa51f03 100644
--- a/webrtc/base/messagequeue.h
+++ b/webrtc/base/messagequeue.h
@@ -209,6 +209,10 @@ class MessageQueue {
   virtual void Quit();
   virtual bool IsQuitting();
   virtual void Restart();
+  // Not all message queues actually process messages (such as SignalThread).
+  // In those cases, it's important to know, before posting, that it won't be
+  // Processed.  Normally, this would be true until IsQuitting() is true.
+  virtual bool IsProcessingMessages();
 
   // Get() will process I/O until:
   //  1) A message is available (returns true)