Prioritize which HTTP requests get a socket first by adding a priority level ...

net/base/client_socket_pool.cc

Index: net/base/client_socket_pool.cc
===================================================================
--- net/base/client_socket_pool.cc	(revision 12453)
+++ net/base/client_socket_pool.cc	(working copy)
@@ -41,7 +41,21 @@
   DCHECK(group_map_.empty());
 }
 
+// InsertRequestIntoQueue inserts the request into the queue based on
+// priority.  Highest priorities are closest to the front.  Older requests are
+// prioritized over requests of equal priority.
+//
+// static
+void ClientSocketPool::InsertRequestIntoQueue(const Request& r,
+                                              RequestQueue* pending_requests) {
+  RequestQueue::iterator it = pending_requests->begin();
+  while (it != pending_requests->end() && r.priority <= it->priority)
+    ++it;
+  pending_requests->insert(it, r);
+}
+
 int ClientSocketPool::RequestSocket(ClientSocketHandle* handle,
+                                    int priority,
                                     CompletionCallback* callback) {
   Group& group = group_map_[handle->group_name_];
 
@@ -51,7 +65,8 @@
     r.handle = handle;
     DCHECK(callback);
     r.callback = callback;
-    group.pending_requests.push_back(r);
+    r.priority = priority;
+    InsertRequestIntoQueue(r, &group.pending_requests);
     return ERR_IO_PENDING;
   }
 
@@ -183,7 +198,7 @@
   if (!group.pending_requests.empty()) {
     Request r = group.pending_requests.front();
     group.pending_requests.pop_front();
-    int rv = RequestSocket(r.handle, NULL);
+    int rv = RequestSocket(r.handle, r.priority, NULL);
     DCHECK(rv == OK);
     r.callback->Run(rv);
     return;