Improve performance of proxy resolver by tracing DNS dependencies.

net/proxy/multi_threaded_proxy_resolver.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/proxy/multi_threaded_proxy_resolver.h"
 
 #include "base/bind.h"
 #include "base/message_loop_proxy.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
@@ skipping 319 matching lines @@
 
 void MultiThreadedProxyResolver::Executor::OnJobCompleted(Job* job) {
   DCHECK_EQ(job, outstanding_job_.get());
   outstanding_job_ = NULL;
   coordinator_->OnExecutorReady(this);
 }
 
 void MultiThreadedProxyResolver::Executor::Destroy() {
   DCHECK(coordinator_);
 
-  // Give the resolver an opportunity to shutdown from THIS THREAD before
-  // joining on the resolver thread. This allows certain implementations
-  // to avoid deadlocks.
-  resolver_->Shutdown();
-
   {
     // See http://crbug.com/69710.
     base::ThreadRestrictions::ScopedAllowIO allow_io;
 
     // Join the worker thread.
     thread_.reset();
   }
 
   // Cancel any outstanding job.
   if (outstanding_job_) {
@@ skipping 100 matching lines @@
     PendingJobsQueue::iterator it =
         std::find(pending_jobs_.begin(), pending_jobs_.end(), job);
     DCHECK(it != pending_jobs_.end());
     pending_jobs_.erase(it);
   }
 }
 
 LoadState MultiThreadedProxyResolver::GetLoadState(RequestHandle req) const {
   DCHECK(CalledOnValidThread());
   DCHECK(req);
-
-  Job* job = reinterpret_cast<Job*>(req);
-  if (job->executor())
-    return job->executor()->resolver()->GetLoadStateThreadSafe(NULL);
   return LOAD_STATE_RESOLVING_PROXY_FOR_URL;
 }
 
-LoadState MultiThreadedProxyResolver::GetLoadStateThreadSafe(
-    RequestHandle req) const {
-  NOTIMPLEMENTED();
-  return LOAD_STATE_IDLE;
-}
-
 void MultiThreadedProxyResolver::CancelSetPacScript() {
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(0u, pending_jobs_.size());
   DCHECK_EQ(1u, executors_.size());
   DCHECK_EQ(Job::TYPE_SET_PAC_SCRIPT,
             executors_[0]->outstanding_job()->type());
 
   // Defensively clear some data which shouldn't be getting used
   // anymore.
   current_script_data_ = NULL;
@@ skipping 92 matching lines @@
     return;
 
   // Get the next job to process (FIFO). Transfer it from the pending queue
   // to the executor.
   scoped_refptr<Job> job = pending_jobs_.front();
   pending_jobs_.pop_front();
   executor->StartJob(job);
 }
 
 }  // namespace net