Improving the fake clock and using it to fix a flaky STUN timeout test.

webrtc/base/messagequeue.cc

Index: webrtc/base/messagequeue.cc
diff --git a/webrtc/base/messagequeue.cc b/webrtc/base/messagequeue.cc
index da50e2304f7a686af4245df733566528d279d185..4c2331bfe603c17cfd5c5376e85ef591bbcacb4d 100644
--- a/webrtc/base/messagequeue.cc
+++ b/webrtc/base/messagequeue.cc
@@ -9,17 +9,14 @@
  */
 #include <algorithm>
 
+#include "webrtc/base/atomicops.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/base/common.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/base/messagequeue.h"
+#include "webrtc/base/thread.h"
 #include "webrtc/base/trace_event.h"
 
-namespace {
-
-enum { MSG_WAKE_MESSAGE_QUEUE = 1 };
-}
-
 namespace rtc {
 
 const int kMaxMsgLatency = 150;  // 150 ms
@@ -41,8 +38,7 @@ bool MessageQueueManager::IsInitialized() {
   return instance_ != NULL;
 }
 
-MessageQueueManager::MessageQueueManager() {
-}
+MessageQueueManager::MessageQueueManager() {}
 
 MessageQueueManager::~MessageQueueManager() {
 }
@@ -108,26 +104,36 @@ void MessageQueueManager::ClearInternal(MessageHandler *handler) {
     (*iter)->Clear(handler);
 }
 
-void MessageQueueManager::WakeAllMessageQueues() {
+void MessageQueueManager::ProcessAllMessageQueues() {
   if (!instance_) {
     return;
   }
-  return Instance()->WakeAllMessageQueuesInternal();
+  return Instance()->ProcessAllMessageQueuesInternal();
 }
 
-void MessageQueueManager::WakeAllMessageQueuesInternal() {
+void MessageQueueManager::ProcessAllMessageQueuesInternal() {
 #if CS_DEBUG_CHECKS  // CurrentThreadIsOwner returns true by default.
   ASSERT(!crit_.CurrentThreadIsOwner());  // See note above.
 #endif
-  CritScope cs(&crit_);
-  for (MessageQueue* queue : message_queues_) {
-    // Posting an arbitrary message will force the message queue to wake up.
-    queue->Post(this, MSG_WAKE_MESSAGE_QUEUE);
+  // Post a delayed message at the current time and wait for it to be dispatched
+  // on all queues, which will ensure that all messages that came before it were
+  // also dispatched.
+  volatile int queues_not_done;
+  auto functor = [&queues_not_done] { AtomicOps::Decrement(&queues_not_done); };
+  FunctorMessageHandler<void, decltype(functor)> handler(functor);
+  {
+    CritScope cs(&crit_);
+    queues_not_done = static_cast<int>(message_queues_.size());
+    for (MessageQueue* queue : message_queues_) {
+      queue->PostDelayed(0, &handler);
+    }
+  }
+  // Note: One of the message queues may have been on this thread, which is why
+  // we can't synchronously wait for queues_not_done to go to 0; we need to
+  // process messages as well.
+  while (AtomicOps::AcquireLoad(&queues_not_done) > 0) {
+    rtc::Thread::Current()->ProcessMessages(0);
   }
-}
-
-void MessageQueueManager::OnMessage(Message* pmsg) {
-  RTC_DCHECK(pmsg->message_id == MSG_WAKE_MESSAGE_QUEUE);
 }
 
 //------------------------------------------------------------------