Optimize the message queue for many active ports with few messages.

runtime/vm/message.cc

Index: runtime/vm/message.cc
diff --git a/runtime/vm/message.cc b/runtime/vm/message.cc
index 807de7ea9ec7101b96619d33fd7c1ae632f68257..73f5da3c76b62652c2ee2c1b52285831e59524c6 100644
--- a/runtime/vm/message.cc
+++ b/runtime/vm/message.cc
@@ -14,9 +14,8 @@ MessageQueue::MessageQueue() {
 
 MessageQueue::~MessageQueue() {
   // Ensure that all pending messages have been released.
-#if defined(DEBUG)
+  Clear();
   ASSERT(head_ == NULL);
-#endif
 }
 
 
@@ -54,31 +53,7 @@ Message* MessageQueue::Dequeue() {
 }
 
 
-void MessageQueue::Flush(Dart_Port port) {
-  Message* cur = head_;
-  Message* prev = NULL;
-  while (cur != NULL) {
-    Message* next = cur->next_;
-    // If the message matches, then remove it from the queue and delete it.
-    if (cur->dest_port() == port) {
-      if (prev != NULL) {
-        prev->next_ = next;
-      } else {
-        head_ = next;
-      }
-      delete cur;
-    } else {
-      // Move prev forward.
-      prev = cur;
-    }
-    // Advance to the next message in the queue.
-    cur = next;
-  }
-  tail_ = prev;
-}
-
-
-void MessageQueue::FlushAll() {
+void MessageQueue::Clear() {
   Message* cur = head_;
   head_ = NULL;
   tail_ = NULL;