Fix purify freeze. Revert "Use a priority queue to assure that subresources are resolved asap"

chrome/browser/net/dns_master.cc

Index: chrome/browser/net/dns_master.cc
diff --git a/chrome/browser/net/dns_master.cc b/chrome/browser/net/dns_master.cc
index 74fb9e5716e3e7003d85737cc668f22165ff3915..bbb450a843f896bba1c6a5064b17a032cb15087e 100644
--- a/chrome/browser/net/dns_master.cc
+++ b/chrome/browser/net/dns_master.cc
@@ -360,24 +360,23 @@ DnsHostInfo* DnsMaster::PreLockedResolve(
   }
 
   info->SetQueuedState(motivation);
-  work_queue_.Push(hostname, motivation);
+  name_buffer_.push(hostname);
+
   PreLockedScheduleLookups();
+
   return info;
 }
 
 void DnsMaster::PreLockedScheduleLookups() {
-  while (!work_queue_.IsEmpty() &&
+  while (!name_buffer_.empty() &&
          pending_lookups_.size() < max_concurrent_lookups_) {
-    const std::string hostname(work_queue_.Pop());
+    const std::string hostname(name_buffer_.front());
+    name_buffer_.pop();
+
     DnsHostInfo* info = &results_[hostname];
     DCHECK(info->HasHostname(hostname));
     info->SetAssignedState();
 
-    if (PreLockedCongestionControlPerformed(info)) {
-      DCHECK(work_queue_.IsEmpty());
-      return;
-    }
-
     LookupRequest* request = new LookupRequest(this, hostname);
     if (request->Start()) {
       pending_lookups_.insert(request);
@@ -390,33 +389,14 @@ void DnsMaster::PreLockedScheduleLookups() {
   }
 }
 
-bool DnsMaster::PreLockedCongestionControlPerformed(DnsHostInfo* info) {
-  // Note: queue_duration is ONLY valid after we go to assigned state.
-  // TODO(jar): Tune selection of arbitrary 1 second constant.  Add plumbing so
-  // that this can be set as part of an A/B experiment.
-  if (info->queue_duration() < base::TimeDelta::FromSeconds(1))
-    return false;
-  // We need to discard all entries in our queue, as we're keeping them waiting
-  // too long.  By doing this, we'll have a chance to quickly service urgent
-  // resolutions, and not have a bogged down system.
-  while (true) {
-    info->RemoveFromQueue();
-    if (work_queue_.IsEmpty())
-      break;
-    info = &results_[work_queue_.Pop()];
-    info->SetAssignedState();
-  }
-  return true;
-}
-
 void DnsMaster::OnLookupFinished(LookupRequest* request,
                                  const std::string& hostname, bool found) {
   AutoLock auto_lock(lock_);  // For map access (changing info values).
   DnsHostInfo* info = &results_[hostname];
   DCHECK(info->HasHostname(hostname));
-  if (info->is_marked_to_delete()) {
+  if (info->is_marked_to_delete())
     results_.erase(hostname);
-  } else {
+  else {
     if (found)
       info->SetFoundState();
     else
@@ -438,9 +418,10 @@ void DnsMaster::DiscardAllResults() {
 
 
   // Try to delete anything in our work queue.
-  while (!work_queue_.IsEmpty()) {
+  while (!name_buffer_.empty()) {
     // Emulate processing cycle as though host was not found.
-    std::string hostname = work_queue_.Pop();
+    std::string hostname = name_buffer_.front();
+    name_buffer_.pop();
     DnsHostInfo* info = &results_[hostname];
     DCHECK(info->HasHostname(hostname));
     info->SetAssignedState();
@@ -516,44 +497,4 @@ void DnsMaster::DeserializeReferrers(const ListValue& referral_list) {
   }
 }
 
-
-//------------------------------------------------------------------------------
-
-DnsMaster::HostNameQueue::HostNameQueue() {
-}
-
-DnsMaster::HostNameQueue::~HostNameQueue() {
-}
-
-void DnsMaster::HostNameQueue::Push(const std::string& hostname,
-    DnsHostInfo::ResolutionMotivation motivation) {
-  switch (motivation) {
-    case DnsHostInfo::STATIC_REFERAL_MOTIVATED:
-    case DnsHostInfo::LEARNED_REFERAL_MOTIVATED:
-    case DnsHostInfo::MOUSE_OVER_MOTIVATED:
-      rush_queue_.push(hostname);
-      break;
-
-    default:
-      background_queue_.push(hostname);
-      break;
-  }
-}
-
-bool DnsMaster::HostNameQueue::IsEmpty() const {
-  return rush_queue_.empty() && background_queue_.empty();
-}
-
-std::string DnsMaster::HostNameQueue::Pop() {
-  DCHECK(!IsEmpty());
-  if (!rush_queue_.empty()) {
-    std::string hostname(rush_queue_.front());
-    rush_queue_.pop();
-    return hostname;
-  }
-  std::string hostname(background_queue_.front());
-  background_queue_.pop();
-  return hostname;
-}
-
 }  // namespace chrome_browser_net